Add ninja format

[Yanis002]

I'm not a ninja expert so lmk if there's a better way, also no idea if this works on Windows (actually I think it should work on Windows if I add sh in the command?)

[AetiasHax]

This could work on Windows, but only if MSYS/Cygwin is installed with the usual GNU commands. I think it would be better if we make ninja format run a new Python script which finds all files and formats them.

Using the clang-format wheel that pre-commit uses, I was able to run clang-format (in a hopefully platform-independent way) like this:

from clang_format import _get_executable
import subprocess

CLANG_FORMAT = _get_executable("clang-format")
subprocess.run(f'{CLANG_FORMAT} --help')

[AetiasHax]

Actually, we could just use the clang-format executable directly in configure.py. So an alternative solution could be to use the get_c_cpp_files function in configure.py to get a list of all files to format, then use the solution above to format each of them.