Rename all the crates to something that crates.io will accept

[tertsdiepraam]

Currently the derive crate is just called derive, which is obviously already taken on crates.io.

Probably:

• uutils-args
• uutils-args-proc
• term-md

But maybe we want to rename to something else first? I don't really care about the name for term-md because it's probably not gonna be used directly, but we're gonna see the name for uutils-args a lot, so it might as well be something nicer.

Some cuter names instead of uutils-args:

• coreopt, crop, corrode, ~coral~ (already taken), corinth, corde, cordial corde could be coreutils deserializer or something.
• optics, optical
• clup, club
• urge
• uopt, uargs, ucli
• I kinda like nucleus, because it has the "u" and "cl" for command line but also it means "core" from coreutils. It's taken on crates.io though. Maybe "nucli"? Gets maybe too close to the nushell things.
• Fun words that start with "u" and are still available: umph, umpteen, upfront, upright, uptight, uranium (also ties in with the previous idea: radioactive -> nuclear)
• enamor is nice too, ties in with the fact that this library uses enums instead of structs to derive from.
• copter

I like the names with a nice connotation: enamor, corde, cordial, etc.

[tertsdiepraam]

Note: we could go for uu_nucleus as crate name and nucleus as the module.

[tertsdiepraam]

I think plain uutils-args and uutils-args-derive is the way to go. A bit boring, but it's the most obvious option.