DOLFINx Python interface installation

Below is guidance for building the DOLFINx Python interface.

1. Build and install the DOLFINx C++ library.

2. Ensure the Python interface build requirements are installed:

      pip install -r build-requirements.txt
   

3. Build DOLFINx Python interface:

      pip install --check-build-dependencies --no-build-isolation .
   

To build in debug and editable mode for development:

 pip -v install --check-build-dependencies --config-settings=build-dir="build" --config-settings=cmake.build-type="Debug"  --config-settings=install.strip=false --no-build-isolation -e .