ci: switch to re-usable workflow from rdmorganiser/.github

[afuetterer]

Description

This is a proposal to move the CI workflows, that can be used by multiple projects (e.g. rdmo, plugin a, plugin b, etc) to rdmorganiser/.github.

At the moment the only re-usable workflow is the lint workflow. It is available at the main branch. But if you like this approach, I will add a tag to the repo.

What do you think?

Types of Changes

• Other (please describe):

Checklist

• I have read the contributor guide.

[afuetterer]

I can move additional jobs into the central .github repo, if you like.

But this PR works as a proof of concept, that a repo can re-use a workflow from a central location, which is nice.

[MyPyDavid]

yes, think it makes sense to move most of the jobs that could be re-used to the .github and maintain them there, thank you!

[afuetterer]

yes, think it makes sense to move most of the jobs that could be re-used to the .github and maintain them there, thank you!

Alright. But let's merge this now, okay? I will submit another PR for the Dev setup job.