Multiple plugin builder/installer

Customize this repo for compiling and installing multiple plugins in one command.

To create an installer for a selection of plugins:

cmake -Bbuild -DCMAKE_INSTALL_PREFIX=./usr/local
# if needed, activate the .venv:
source .venv/bin/activate
cmake --build build -j6
cmake --build build -t package

NOTE: some of the plugins depend on a Python virtual environment. If one venv is already loaded, then the CMake scripts uses it. Iv a local .venv directory des not exist, the CMake script creates it during configuration and installs numpy and rerun-sdk, then you have to manually activate it before the build phase. Finally, if a local .venv exists but it is not activate, CMake stops with an error.