[cmake,py] Python modules are usable without OGS_USE_PIP=ON.

See merge request !5242

If dependencies such as pytest etc. are installed by some other means you can run
e.g. the pytest-based tests.

[cmake] Proper OpenMP linking on Windows.

See merge request ogs/ogs!5235

[web] python dev instructions

See merge request ogs/ogs!5240

[HMPhaseField] add hydromechanical phase-field process

See merge request ogs/ogs!4809

[TwoPhaseFlowWithPP] Missed saturation variable setting

See merge request !5214

[doxygen] Fix qa link to GitLab.

See merge request !5234

implement parallel assembly for Small Deformation

See merge request ogs/ogs!5220

Slightly relax ctest tolerances

See merge request ogs/ogs!5233

Some were marked as such but were not (MaterialForces),
and others had prefixed _ instead of a suffix.

[IO/XDMF] Fix bug for output of line in mixed element case

Closes #3524

See merge request ogs/ogs!5231

Avoid dead-lock in MPI when AssemblyException is thrown

See merge request !5227

see documentation https://xdmf.org/index.php/XDMF_Model_and_Format#Topology

Implementation for topology type ParentDataType::POLYLINE and other
ParentDataTypes is identical

The copyResiduumVectorToBulkMesh requires MPI communication and
especially a finalized petsc vector, which didn't happen
before when an AssemblyException was thrown.
Now the exception is stored temporarily, the failure is synchronised,
and all ranks abort; the ranks with the exception rethrow the
exception.

Simplifies usage in the NonlinearSolver in the synchronisation
of failed assemblies.

[NL] reuse inverse jacobian / reuse inv. jacobian once every n steps

See merge request ogs/ogs!5221