Fix/import lib resources
See also MR in finesse3 repo: https://gitlab.com/ifosim/finesse/finesse3/-/merge_requests/195
This fixes some uses of importlib.resources
that were deprecated in python 3.11. It also removes the setup for the multiproject pipeline for testing finesse against finesse-ligo (this is now done internally in the finesse pipeline, see the linked MR)
Also updates the python version for the tests to 3.11, could be reverted but would be nice to keep up to date.