T6758: Add build package xen-guest-agent

[sever-sever]

Change Summary

The xen-guest-agent could be used for XCP-NG images

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/T6758

Component(s) name

Proposed changes

How to test

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

[github-actions]

👍
No issues in PR Title / Commit Title

[sever-sever]

@Mergifyio backport circinus

[mergify]

backport circinus

✅ Backports have been created

• #789 T6758: Add build package xen-guest-agent (backport #788) has been created for branch circinus

[dmbaturin]

There is a peculiarity there. By default, the xenstore-rs crates links against the system libxenstore.so, but the Debian packaging doesn't have that dependency so building with default flags will result in a broken installation, unless libxenstore is installed by hand.

See my MR in the upstream for details: https://gitlab.com/xen-project/xen-guest-agent/-/merge_requests/86