Allow to create workspace

[jorisv]

This PR aims to allow project using jrl-cmakemodules to be used under the same root CMakeLists.txt (workspace).

• Use unique target name (prefixed by project name)
• Keep old target as aggregators
• Allow to deactivate the automatic call to setup_project_finialize (called in the workspace CMakeLists.txt instead of the project CMakeLists.txt)
• Reformat some custom_target
• PROJECT_PACKAGES_IN_WORKSPACE that should avoid running find_package in ADD_PROJECT_DEPENDENCY and ADD_PROJECT_PRIVATE_DEPENDENCY on project already in the workspace
• Add ADD_PROJECT_PRIVATE_DEPENDENCY that check for PROJECT_PACKAGES_IN_WORKSPACE before calling find_package
• Add PROJECT_PYTHON_PACKAGES_IN_WORKSPACE to include Python modules from workspace in PYTHONPATH
• Use PROJECT_SOURCE_DIR and PROJECT_BINARY_DIR instead of CMAKE_SOURCE_DIR and CMAKE_BINARY_DIR since the

dist and doc target is working with multiple project but distcheck is not working. Since distcheck do some very heroic thing with the CMakeCache.txt, I don't think we can make it work for multiple project.

[nim65s]

Thanks for this work ! This is still a draft, but can it be reviewed / tested yet, or should I wait a bit ?

[jorisv]

I will push similar PR on:

• eigenpy
• hpp-fcl
• pinocchio
• pycppad
• example-robot-data
• proxsuite
• proxsuite-nlp
• aligator

I will also create a new repository called simple-robotics/workspace that will store the root CMakelists.txt and probably some scripts to populate the workspace.

[jorisv]

I keep this PR as a draft until I'm sure all modified project still build in standalone mode in the CI.

[jorisv]

@nim65s If you want to test it, I have uploaded the workspace repository.

If the README.md is hard to understand or you encounter some issues please add some comment in this PR