feat: support reloading progress and error for dae reload

[mzz2017]

Background

In the past, dae reload always returned OK. When the reload failed, we had no way of knowing what error occurred and could only obtain the failure information by viewing the dae log.

This PR supports dae reload to wait for the reloading progress and print error information when an error occurs.

Specifically, /var/run/dae.progress is introduced; dae will write its status to this file during the reloading process, thus dae reload can read the current reloading status of dae from this flie.

Checklist

• The Pull Request has been fully tested
• There's an entry in the CHANGELOGS
• There is a user-facing docs PR against https://github.com/daeuniverse/dae

Full Changelogs

• [Implement ...]

Issue Reference

Closes #[issue number]

Test Result

[sumire88]

LGTM

[dae-prow]

🧪 Since the PR has been fully tested, please consider merging it.