smoketest: T5558: Extend configtest to allow checking of migration script results

[sarthurdev]

Change Summary

• Extends config smoketest to check resulting migrated CLI nodes against a file of expected nodes
• Includes list of expected CLI nodes for tests basic-vyos and dialup-router-medium-vpn

Will add further configs/expected CLI for major migrated components (e.g. firewall/zone-policy) over time.

Note: As future migrations are added that change syntax, tests may need to be updated.

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Code style update (formatting, renaming)
• Refactoring (no functional changes)
• Migration from an old Vyatta component to vyos-1x, please link to related PR inside obsoleted component
• Other (please describe):

Related Task(s)

• https://vyos.dev/T5558

Component(s) name

smoketest

Proposed changes

How to test

Run make testc, after migration is loaded and committed, it will check config commands in the config-tests file (if present) against the effective config.

Checklist:

• I have read the CONTRIBUTING document
• I have linked this PR to one or more Phabricator Task(s)
• I have run the components SMOKETESTS if applicable
• My commit headlines contain a valid Task id
• My change requires a change to the documentation
• I have updated the documentation accordingly