feat: Add AutoNAT behavior

[bgins]

Description

This PR makes the following changes:

• Add AutoNAT behavior to probe for public listen addresses
• Update external_addresses with reported public addresses
• Add StatusChangedAutonat notification
• Add NatStatus extension trait with to_tuple helper
• Confirm addresses observed on identify events with an AutoNAT probe
• Minor refactoring in settings

When the NatStatus changes to public, the reported address is added to external_addresses. If a previously reported address transitions from public to private or unknown, the address is removed from external_addresses.

Note that announce_addresses are always kept in external_addresses and will not be removed by changes to NatStatus.

Link to issue

Implements #398

Type of change

• New feature (non-breaking change that adds functionality)
• Refactor (non-breaking change that updates existing functionality)
• This change requires a documentation update

Test plan (required)

This PR adds the following tests:

• AutoNAT confirms a reachable address
• StatusAutoNat notification to and from IPLD bytes and JSON tests
• Test NatStatus to_tuple returns expected tuples

[codecov]

Codecov Report

Attention: Patch coverage is 65.78947% with 65 lines in your changes are missing coverage. Please review.

Project coverage is 69.81%. Comparing base (2d0cfe9) to head (8e39d28).

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #632      +/-   ##
==========================================
- Coverage   69.85%   69.81%   -0.05%     
==========================================
  Files          98      100       +2     
  Lines       13394    13577     +183     
==========================================
+ Hits         9357     9479     +122     
- Misses       4037     4098      +61     

Files	Coverage Δ
homestar-runtime/src/event_handler/notification.rs	65.21% <ø> (ø)
homestar-runtime/src/libp2p/nat_status.rs	100.00% <100.00%> (ø)
homestar-runtime/src/network/swarm.rs	72.34% <100.00%> (+1.61%)	⬆️
homestar-runtime/src/settings.rs	98.45% <ø> (ø)
homestar-runtime/src/settings/libp2p_config.rs	100.00% <100.00%> (ø)
...-runtime/src/event_handler/notification/network.rs	95.41% <96.15%> (+0.03%)	⬆️
.../src/event_handler/notification/network/autonat.rs	93.87% <93.87%> (ø)
homestar-runtime/src/event_handler/swarm_event.rs	22.07% <8.95%> (-0.99%)	⬇️

... and 1 file with indirect coverage changes

[zeeshanlakhani]

Damn good stuff @bgins.

[zeeshanlakhani]

👍🏽