ci: only build ros2-ws and ros2-control

[domire8]

Description

• Future of base image #94

This one hurts a bit because it removes a lot of code that took some effort to make it work hehe. But as discussed in the topic, we only want to build ros2-ws and ros2-control images and then just add control-libraries and modulo as desired. For that we can remove all the workflows that check if those two repos have new changes. Additionally, there is now also a build with a manifest merge now, such that all pushed images have a proper tag.

Review guidelines

Estimated Time of Review: 10 minutes

Checklist before merging:

• Confirm that the relevant changelog(s) are up-to-date in case of any user-facing changes

[eeberhard]

It's definitely cleaner and the deleted code is not lost, since we absorbed it all as knowledge and lessons learned along the way!

As a side note, how do you feel about tagging the ros2-control image with the version (for example, as :iron and :iron-3.18)? That way if we keep iron but upgrade ros2_control to some other version later, we can distinguish them. Not in scope for this PR but goes in a similar direction and I think would be useful to do.

[domire8]

Yes, I guess that would make sense. Not sure how we would extract that though because technically it's not just the ros2control version that represents that image but also the combination of all the other repos that we have to clone.

[LouisBrunner]

I think we should just make our own version for this. e.g. v2.3.0+iron

[domire8]

I think we should just make our own version for this. e.g. v2.3.0+iron

Fair suggestion, do we take the version from a VERSION file?

[domire8]

Let's continue discussing in #82 . Is this one good to go?