Compute the list of .rb files at package generation time and install it in the package folder

[jmarrec]

The OpenStudio SDK CMake configure call spends an awful amount of time doing

Searching for ruby modules in '/Users/julien/.conan/data/openstudio_ruby/2.7.2/nrel/testing/package/b0b153961e79d4e95517b97d888ce78a877ec1ef/lib/**/*.rb'

https://github.com/NREL/OpenStudio/blob/c665b9fc52efde300e45b967498e2f7b9fdeb7b6/ruby/engine/CMakeLists.txt#L24-L191

We could save this time by doing it when we generate the package instead of everytime we call CMake.

The same should be done in openstudio-gems.

FYI @tijcolem (I just thought of this)

[jmarrec]

Actually it's more the actual embed_files call that takes a long time

end search ruby: 20230317 20:10:02
end search ruby: 20230317 20:10:02
start search gems: 20230317 20:10:02
end search gems: 20230317 20:10:04
end actual embbed: 20230317 20:10:24
```