Drop make build system

Here we at long last remove the `make`-based build system, it having
been replaced with the Shake-based Hadrian build system. Users are
encouraged to refer to the documentation in `hadrian/doc` and this [1]
blog post for details on using Hadrian.

Closes #17527.

[1] https://www.haskell.org/ghc/blog/20220805-make-to-hadrian.html