Add licenses to lots of compilers (#4305)

* Add Rust license info

* Add hipclang license info

Same as C++'s rocm one

* Add license info for Ada compilers

* Add licenses to most C compilers

* Add license to Nim compiler

* Add license to FPC

* Add license to Python

* Add license to Zig

* Add licenses for Scala

Separates it between 2 and 3 as it changed quite a lot,
so that we can more easily add new versions to it in the future

* Add license for Pony compiler

* Add Ocaml license

* Add Mlir license

* Add license to LLVM pseudolang

* Fix mlir license props

* Add license to Kotlin

* Add OpenJDK license

* Add Jakt license

* Add GHC licenses

* Remove licenses from platspec compilers

* Add C++ licenses

* Add link to open issue if license is wrong

* Fix button link