Error properly on startup

[rtibbles]

Summary

• Resolves a regression caused by Remove cherrypy dependency #8026 whereby errors occurring during plugin life cycle events would then cause an error in their handling.
• Does this by letting the handler function take arbitrary *args, to match the signature of the magicbus error state handlers: https://github.com/cherrypy/magicbus/blob/main/magicbus/process.py#L101
• Simplifies service shutdown by only makes the call to shutdown the worker threads once, and makes it blocking
• Adds a handle_SIGINT method to give different logging when a SIGINT signal is called versus SIGTERM

References

Fixes #8119

Reviewer guidance

Make sure Kolibri starts up properly and then reacts properly to CTRL-C, or throwing any error during a call to register the zero conf service, or start one of the worker threads.

Noting that I have observed recently that a command prompt will display and then further logging text will happen after the CTRL-C - I am at a loss to work out how to prevent this, as the way that magicbus handles signal handlers is the way that every StackOverflow post recommends to try to handle this, so I am at a loss as to how to resolve it.

---

Testing checklist

• Contributor has fully tested the PR manually
• If there are any front-end changes, before/after screenshots are included
• Critical user journeys are covered by Gherkin stories
• Critical and brittle code paths are covered by unit tests

PR process

• PR has the correct target branch and milestone
• PR has 'needs review' or 'work-in-progress' label
• If PR is ready for review, a reviewer has been added. (Don't use 'Assignees')
• If this is an important user-facing change, PR or related issue has a 'changelog' label
• If this includes an internal dependency change, a link to the diff is provided

Reviewer checklist

• Automated test coverage is satisfactory
• PR is fully functional
• PR has been tested for accessibility regressions
• External dependency files were updated if necessary (yarn and pip)
• Documentation is updated
• Contributor is in AUTHORS.md

[jredrejo]

Tested without issues, and code LGTM