feat: versioning modules

[xynydev]

This PR adds a new GH workflow (build-individual.yml) and an accompanying script (build-individual.nu) that builds modules into separate containers and tags them properly, including building all versions of versioned modules.

A lot is yet unimplemented. Currently the builds are pretty fast even without utilizing GH jobs, since nothing is pushed to the web. I didn't have the energy to bother with figuring out the GHA matrix generation stuff as there were some errors I couldn't solve, so I just though, why not make it all one script lol...

[gmpinder]

I am in love with nushell purely from seeing it in this PR alone

[xynydev]

The build-invidual.nu script is functionally done now. Next steps;

• Secondary script & build to replace the current build.yml
  • This one would generate only one container, ghcr.io/blue-build/modules, with just the latest version of each module.

[xynydev]

Since modules.json is now handled by the website and the other stuff is handled by CLI, this PR is basically ready now. It is now capable of building and tagging the individual module containers as well as a unified module container containing the latest version of every official module.

Reviews from all appreciated, @gmpinder as the CLI implementer should take a closer look. After this is merged we can start implementing default-flatpaks v2 with @fiftydinar. I'll move the other TODO items in my last post to the tracking issue #208.

Edit:
I decided to keep the v1 folder in default-flatpaks, because we're likely to make v2 soon, and that serves as a good starting point to using versioning. It's also a good test for the functionality in this PR.

[gmpinder]

I'll do a deeper review when I'm at my computer

[xynydev]

@fiftydinar final approves for this so we can merge?