Make Knip and Jest workflows reusable

[gentlementlegen]

          @0x4007 I would propose to convert the Knip workflow into a reusable workflow (https://docs.github.com/en/actions/using-workflows/reusing-workflows) . There is a correct Knip setup now but it needs to be propagated into multiple repositories. The differences between Knip workflow configurations between repositories are minor: bun vs yarn and different yarn versions. I can work on this as soon as I finish the plugin screencasts.

Originally posted by @gitcoindev in https://github.com/ubiquibot/permit-generation/issues/35#issuecomment-2216602242

What we are aiming to solve is the changes needed within all the repositories that inherited from the template when we are fixing a workflow. Having it as a template could solve the synching thus not requiring to update all the workflows across the repositories. This change also applies to https://github.com/ubiquity/ts-template/

[rndquu]

The following workflows could be refactored to be reusable:

• conventional commits (plugin-template, ts-template)
• cspell (plugin-template, ts-template)
• knip-reporter (plugin-template, ts-template)
• knip (plugin-template, ts-template)