Add action for slic configuration

[shvlv]

The PR adds the reusable action for slic configuration. It will be helpful to run tests in CI. I think two inputs should be enough for most cases (maybe I missed something). Anyway, action can be improved if more feedback is provided.

Regarding the complete workflow, I guess it might be useful as well, but the building step is more complicated. So I decided to add just an example that can be copied and adapted per-project needs. Maybe it could be a reusable workflow in the future (with partially the same steps as zip.yml has).

[defunctl]

Looking good, a couple more suggestions and questions

[shvlv]

Thanks, @defunctl, it makes sense! I've applied your suggestions.

[defunctl]

Just a couple of grammar things I missed

[defunctl]

This looks good to me now, you might want to wait for @borkweb to give it a look over as well.

[borkweb]

I love this addition! Nice work 🥇