libcamera CMake wrapper

This implements a thin CMake wrapper around the libcamera meson project. It only builds the main library without examples, tests or documentation.

cmake -B build -GNinja
cmake --build build

The number of parallel processes can be limited by setting NJOBS:

cmake -B build -GNinja -DNJOBS=2
cmake --build build

When using this as part of a colcon workspace, NJOBS can be set via --cmake-args:

colcon build --cmake-args="-DNJOBS=2"