Universe.dimensions is fixed, even if barostat is applied

During the refinement process the MD engines can update or reset the atomic configuration passed to the MD engine, eg here: https://github.com/MDMCproject/MDMCv0.2_pilot/blob/3597a5bc697e7e3f2e6c9c2b5cb5cb8ea705e1fb/MDMC/MD/engine_facades/lammps_engine.py#L691
and here:
https://github.com/MDMCproject/MDMCv0.2_pilot/blob/3597a5bc697e7e3f2e6c9c2b5cb5cb8ea705e1fb/MDMC/MD/engine_facades/lammps_engine.py#L721
However, this does not include the size of the box/cell that the MD engine uses, which is specified in `Universe.dimensions`. For certain `Ensemble`s, i.e. any that include a barostat such as `npt` or `nph`, the cell size should be allowed to change.