Hi all!

NEST is pip installable! I'd like to collect some feedback on #2073 https://github.com/nest/nest-simulator/pull/2073 so anyone that is interested to try out a (temporary) pip installed NEST can try `pip install nest-on-square-wheels`. It takes as long as a regular NEST install so it can take a while to finish. In case of errors the error message is usually buried in quite a big red blob of pip mumbo jumbo, but other than that it should be a nice hands-off experience :)

You can build with MPI:

pip install nest-on-square-wheels --install-option="--mpi=ON"

and control the amount of CMake jobs if it makes your machine stall:

pip install nest-on-square-wheels --install-option="--mpi=ON"

--install-option="--jobs=2"

All feedback is welcome on the PR, these temporary `nest-on-square-wheels` will be removed in the near future so obviously don't count on them in any scripts or package lists.