Replace PackageCompiler with juliac

[visr]

This is on top of #2440.
It replaces PackageCompiler with the juliac script to compile libribasim.
Note that it uses --trimming=no because we don't support that yet.

Advantages

• easy to work on trimming support
• lower level interface makes it easier to control what we want to include
• faster (some double compilation seems to be happening in PackageCompiler)

Disadvantages

• the juliac interface is subject to change
• we need to do a few things PackageCompiler did for us, like copying shared libraries
• not clear yet what needs to be done for relocatable artifacts, preferences

TODO

• update build/README.md
• remove PackageCompiler from env

I'm closing this directly since I think it is better to stick to PackageCompiler for now, hopefully it will build on or catch up to juliac in the future, then we can use that.

Taking libribasim.jl out of Ribasim is something that might be interesting anyway. Also I assume that in time we can remove julia_init like done in 48a5605.