Add some Module examples

[karpfediem]

I will be adding some more example modules here that I am using, which I can share.

This is a Work In Progress for now and I'm happy to improve upon these.

The changes of this MR should remain limited to the modules/ directory.

[purpleidea]

Nice! If you want to rename the bash commit properly, I could cherry-pick/merge that one.

For the mcl stuff, needs tabs instead of spaces.

[karpfediem]

Making tests work properly under NixOS took me a bit longer than anticipated.
I will add module descriptions soon, but at another time.

[purpleidea]

Overall the whole thing fails, but if the shebang commits and other bits are ready to be cherry-picked, maybe put those in a separate PR so I can see it passes and I can pull those in early.

[purpleidea]

(Doesn't need to pass the race tests, just the basic and shell.)

[karpfediem]

Overall the whole thing fails, but if the shebang commits and other bits are ready to be cherry-picked, maybe put those in a separate PR so I can see it passes and I can pull those in early.

Sorry, but i think it's not ready yet afterall. There are many more cases of FHS filepaths.
For now i have fixed my own issues using a shell with emulated FHS paths.
I would like to rather address it all at the same time in a separate issue after giving it some more thought.

EDIT: split some of it out into #801 and #802

[purpleidea]

FYI: I cherry-picked/merged/etc most of this. You may wish to rebase at some point or open a new PR.