feat(just): Add RHEL Toolboxes and UBI Images

[noelmiller]

This is to fix: #106

I decided to go with the official toolbox images for RHEL which will require users to log in. I did add a check to confirm the user is logged in to registry.redhat.io before attempting to create the distrobox.

For the UBI images, I went with the URL that does not require authentication to pull them down.

[bsherman]

I made a recent comment on #106 which may provide a bit of context for this change request:

I think this effort of adding the RHEL distroboxes is excellent, but unless I was mistaken, I thought we were hoping to use toolbox for it.

So, maybe the compromise is have both?

So I have 2 possible suggestions:

1. in this PR, simply duplicate the distrobox-rhel* recipes, but as toolbox-rhel* using toolbox instead.
   It would obviously work fine and be good for uses wanting either.

2. we could merge this as is, but maybe add an argument to all our distrobox recipes which allows toggling toolbox, and perhaps allows setting an env var which defaults to toolbox. The idea people that some users definitely do use it exclusively.

[noelmiller]

Giving users a choice definitely is better in my opinion (but I think we should default to distrobox). I'm not as familiar with Toolbox as I am with distrobox.

That being said, it might make sense to have a separate just file specifically for toolbox since it is a different tool. Is it possible to import variable files into justfiles? That way, we could define all of our containers we want to use and make them available to both toolbox and distrobox.

[bsherman]

Giving users a choice definitely is better in my opinion (but I think we should default to distrobox).

I agree, mostly from the position that our just recipes are all, already distrobox-*

That being said, it might make sense to have a separate just file specifically for toolbox since it is a different tool.

Per the newer restructured just recipe files, yes, I think that could make sense, but, also that seems like a lot of duplication instead of DRY.

Is it possible to import variable files into justfiles? That way, we could define all of our containers we want to use and make them available to both toolbox and distrobox.

Yes. This latter thought is basically what I was suggesting in my second option...

I'd be happy to merge this as is, but file a follow-up issue to be more "toolbox-friendly" and either coach you through the env var stuff or provide the PR myself.

[noelmiller]

Follow up issue would be great! I'm happy to work together on this to get more familiar with just. I was just reading that you can use environment variables and export them. There are also parameters as well which we could explore!

[bsherman]

Per our discussion, I've created #186 and I approve these changes.

[KyleGospo]

This looks great to me, don't even need to create the distrobox-* images now that distrobox overrides xdg-open. +1