[Nexthop][fboss2-dev] Add CLI command for configuring trunk VLAN

[hillol-nexthop]

Based on #1096

Pre-submission checklist

• I've ran the linters locally and fixed lint errors related to the files I modified in this PR. You can install the linters by running pip install -r requirements-dev.txt && pre-commit install
• pre-commit run

Summary

This PR implements trunk VLAN management functionality for the FBOSS CLI, allowing users to add and remove VLANs from trunk ports.

config interface <port-list> switchport trunk allowed vlan add <vlan-id-list>
config interface <port-list> switchport trunk allowed vlan remove <vlan-id-list>

Examples:

# Add VLANs 100, 200, 300 to trunk port eth1/1/1
fboss2-dev config interface eth1/1/1 switchport trunk allowed vlan add 100,200,300

# Add VLAN 100 to multiple ports
fboss2-dev config interface eth1/1/1-eth1/1/4 switchport trunk allowed vlan add 100

# Remove VLAN 200 from trunk port
fboss2-dev config interface eth1/1/1 switchport trunk allowed vlan remove 200

Implementation Details
Adding VLANs: Creates VlanPort entries with emitTags=true (tagged traffic) for each port-VLAN combination
Removing VLANs: Removes the corresponding VlanPort entries from the configuration
Validation:
VLANs must exist in the configuration with an associated interface (SVI)
Ports must exist in the hardware platform mapping
VLAN IDs must be in the valid range (1-4094)
Idempotency: Adding an existing VLAN or removing a non-existent VLAN reports "No changes made" without error

Files Changed
fboss/cli/fboss2/commands/config/interface/switchport/trunk/ - New command hierarchy
fboss/cli/fboss2/utils/CmdUtils.h/cpp - Added TrunkVlanAction argument type
fboss/cli/fboss2/CmdList.cpp - Registered new commands
fboss/cli/fboss2/CmdArgsLists.h - Added argument type mapping

Test Plan

AddAndRemoveTrunkVlan
AddMultipleVlans
AddExistingVlan
RemoveVlansOneByOne
RemoveNonExistingVlan
AddVlanToMultiplePorts
RemoveVlanFromMultiplePorts
AddMultipleVlansToMultiplePorts