vyos-op-run: T8306: improve debug logging and error reporting

[dmbaturin]

Change summary

Since vyos-op-run is a native executable, it's impossible to edit it in-place to add debug messages, so it's probably a good idea to add as much built-in debug logging as possible.

(Since log formatting functions are stored in thunks, they have no performance impact when debug is not enabled)

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): internal change.

Related Task(s)

Related PR(s)

Checklist:

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

[jestabro]

Extend debug messages and error reporting; sanity check build and run was performed.

[sever-sever]

Extend vyos-op-run for debugging/logging