feat(anta.tests): Adding the test case to verify BFD session and timers

[MaheshGSLAB]

Description

Add the test case to verify the BFD session and timers.

Run the testcase by adding catalog as below:

anta.tests.bfd:
  - VerifyBFDSpecificPeers:
      bfd_peers:
        - peer_address: 192.0.255.8
          vrf: default
        - peer_address: 192.0.255.7
          vrf: default
  - VerifyBFDPeersIntervals:
      bfd_peers:
        - peer_address: 192.0.255.8
          vrf: default
          tx_interval: 1200000
          rx_interval: 1200000
          multiplier: 3
        - peer_address: 192.0.255.7
          vrf: default
          tx_interval: 1200000
          rx_interval: 1200000
          multiplier: 3

1. Testcase pass when details are correct.

                                                                    All tests results                                                                     
┏━━━━━━━━━━━┳━━━━━━━━━━━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━┳━━━━━━━━━━━━┳━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━┓
┃ Device    ┃ Test Name               ┃ Test Status ┃ Message(s) ┃ Test description                                                       ┃ Test category ┃
┡━━━━━━━━━━━╇━━━━━━━━━━━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━╇━━━━━━━━━━━━╇━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━┩
│ s1-spine1 │ VerifyBFDPeersIntervals │ success     │            │ Verifies the timers of the BFD peers in the specified VRF.             │ bfd           │
├───────────┼─────────────────────────┼─────────────┼────────────┼────────────────────────────────────────────────────────────────────────┼───────────────┤
│ s1-spine1 │ VerifyBFDSpecificPeers  │ success     │            │ Verifies the BFD peer's sessions and remote disc in the specified VRF. │ bfd           │
└───────────┴─────────────────────────┴─────────────┴────────────┴────────────────────────────────────────────────────────────────────────┴───────────────┘

2. Testcase fails when bfd neighbor not found.

                                                                                          All tests results                                                                                           
┏━━━━━━━━━━━┳━━━━━━━━━━━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━┓
┃ Device    ┃ Test Name               ┃ Test Status ┃ Message(s)                                                     ┃ Test description                                              ┃ Test category ┃
┡━━━━━━━━━━━╇━━━━━━━━━━━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━┩
│ s1-spine1 │ VerifyBFDSpecificPeers  │ failure     │ Following BFD peers are not configured, status is not up or    │ Verifies the BFD peer's sessions and remote disc in the       │ bfd           │
│           │                         │             │ remote disc is zero:                                           │ specified VRF.                                                │               │
│           │                         │             │ {'192.0.255.81': {'MGMT': 'Not Configured'}, '192.0.255.71':   │                                                               │               │
│           │                         │             │ {'default': 'Not Configured'}}                                 │                                                               │               │
├───────────┼─────────────────────────┼─────────────┼────────────────────────────────────────────────────────────────┼───────────────────────────────────────────────────────────────┼───────────────┤
│ s1-spine1 │ VerifyBFDPeersIntervals │ failure     │ Following BFD peers are not configured or timers are not       │ Verifies the timers of the BFD peers in the specified VRF.    │ bfd           │
│           │                         │             │ correct:                                                       │                                                               │               │
│           │                         │             │ {'192.0.255.81': {'MGMT': 'Not Configured'}, '192.0.255.71':   │                                                               │               │
│           │                         │             │ {'default': 'Not Configured'}}                                 │                                                               │               │
└───────────┴─────────────────────────┴─────────────┴────────────────────────────────────────────────────────────────┴───────────────────────────────────────────────────────────────┴───────────────┘

3. Testcase fails when BDF neighbor session is not up and timers are not correct.

 
                                                                                          All tests results                                                                                           
┏━━━━━━━━━━━┳━━━━━━━━━━━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━┓
┃ Device    ┃ Test Name               ┃ Test Status ┃ Message(s)                                                     ┃ Test description                                              ┃ Test category ┃
┡━━━━━━━━━━━╇━━━━━━━━━━━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━┩
│ s1-spine1 │ VerifyBFDPeersIntervals │ failure     │ Following BFD peers are not configured or timers are not       │ Verifies the timers of the BFD peers in the specified VRF.    │ bfd           │
│           │                         │             │ correct:                                                       │                                                               │               │
│           │                         │             │ {'192.0.255.8': {'default': {'tx_interval': 1200000,           │                                                               │               │
│           │                         │             │ 'rx_interval': 1200000, 'multiplier': 3}}, '192.0.255.7':      │                                                               │               │
│           │                         │             │ {'default': {'tx_interval': 1200000, 'rx_interval': 1200000,   │                                                               │               │
│           │                         │             │ 'multiplier': 3}}}                                             │                                                               │               │
├───────────┼─────────────────────────┼─────────────┼────────────────────────────────────────────────────────────────┼───────────────────────────────────────────────────────────────┼───────────────┤
│ s1-spine1 │ VerifyBFDSpecificPeers  │ failure     │ Following BFD peers are not configured, status is not up or    │ Verifies the BFD peer's sessions and remote disc in the       │ bfd           │
│           │                         │             │ remote disc is zero:                                           │ specified VRF.                                                │               │
│           │                         │             │ {'192.0.255.8': {'default': {'status': 'down', 'remote_disc':  │                                                               │               │
│           │                         │             │ 0}}, '192.0.255.7': {'default': {'status': 'down',             │                                                               │               │
│           │                         │             │ 'remote_disc': 0}}}                                            │                                                               │               │
└───────────┴─────────────────────────┴─────────────┴────────────────────────────────────────────────────────────────┴───────────────────────────────────────────────────────────────┴───────────────┘

Fixes #499

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my code
• I have run pre-commit for code linting and typing (pre-commit run)
• I have made corresponding changes to the documentation
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes (tox -e testenv)

[carl-baillargeon]

LGTM. Please check my comment on inputs if it's possible or not.

[titom73]

LGTM