feat: Include just scripts for changing & factory-resetting user-configuration of modules

[fiftydinar]

Inspired from this:

https://github.com/blue-build/modules/issues/157

This would make users more aware that they can change some module options & it would make that process more intuitive and easier.

F.e.

• just default-flatpaks - lists possible configuration options with CLI selection
• just default-flatpaks install-system - directly sends user to modify system install list
• just default-flatpaks install-user - directly sends user to modify user install list
• just default-flatpaks reset - resets user configuration to factory defaults

Tricky part of this is support for operating systems other then Universal Blue. In that case, we can either install just package as a dependency if it doesn't exist, or we can make a generic bash script intended for this usage only.

Another tricky part is usage of ujust in Universal Blue instead of just, which would make our commands less universal.

Universal Blue also includes their separate config made by @HikariKnight called ugum, which makes CLI selection & quick options possible. ugum is another Universal Blue exclusive, which would make this process a bit harder. Although, ugum is bash-compatible, so it's not the hardest part.

[HikariKnight]

ugum is compatible with normal just as i wanted it to be self contained. ujust is just a script to make sure just always runs inside bash, since it does not work correctly in shells like fish or something

[xynydev]

The main issue with this I see is compatibility, ince we aim to support multiple OS base images, but ublue is the only one with an unified system for default just commands and just pre-included. This would necessitate one of the following:

• Only support just when basing on Universal Blue
  • Need to implement detection
• Re-implement Universal Blue's just setup (or something compatible) for all supported images.
• Figure out how to pull in conditionally and make use of Universal Blue's just system for all supported images.

Introducing just on all images might add bloat (bling✨) the user might not always want when using default-flatpaks or another module making use of this system. This would make it necessary to include an option for whether to use just in each module utilizing it, along with doing the just setup with each module required.

I'm not sure if all that is worth it for making just commands that are equivalent to doing rm -rf ... && cp -r ... or launching a pre-existing shell script.

[fiftydinar]

I will close this issue for now, as It's concluded that this inclusion would be complex, with small gains, due to compatibility factor.

If something changes in the future, I can reopen this issue.