[PSRule] Run PSRule pre-flight validation on the whole library (scheduled pipeline)

[eriqua]

This issue is about implementing a scheduled pipeline to run PSRule validation checks on the whole repository.

This is useful to provide an overview of all failing checks per module overtime (if any).

A status badge should also be added to the repo home page.

Note: the same has been planned for Linter and broken link checks as commented in issue #2363

PR #2094 hosts a PoC triggered on pull request.

[eriqua]

Suggestion: Move to todo and complete as first.
Implementation is almost ready in branch hack/topic6