MLX in C++ example

[awni]

Adds:

• Very minimal example project using MLX in C++ with Cmake
• Documentation page on the same in the developer docs
• Convenience commands to get the --cmake-dir and --version using mlx as a python package. E.g. python -m mlx --cmake-dir gets the cmake directory for find_package. Simplifies using MLX in CMake as a dependency.

[angeloskath]

I love this :-)

So far I have been building a separate mlx library for C++ dev. Didn't think of making this.