Split the PR actions of the vulncheck evaluator into a proper remediate action

[jhrozek]

The vulncheck evaluator does two things - checks the vulnerabilities and then performs an action based on the vulnerabilities found, like suggesting PR changes or commenting with a summary. This was all coded before we had remediations, but now that we do have a proper remediations engine we should split the actions part of the evaluator into a proper remediate module to avoid turning the vulncheck into spaghetti (esp visible once we started adding Pi support in addition to vulnerabilities)

[github-actions[bot]]

This issue is stale because it has been open 30 days with no activity. Remove stale label or comment or this will be closed in 5 days.

[jhrozek]

When addressing this, please take comments in https://github.com/stacklok/minder/pull/2171 into account

[mesembria]

Closing, will address as part of an upcoming epic.