petsc4py: add test for equality constraints callbacks

petsc4py plex: orient and then refine in testAdapt
- The mesh only has 6 elements, so we need to refine in order for all 4 procs to have entities.

Merge branch 'stefanozampini/petsc4py' into 'main'

Some work on petsc4py

See merge request petsc/petsc!4644

petsc4py: allow snes.solve to use the internal solution vector

petsc4py: add option to disable memory leak check

this is useful when debugging failures of the python interpreter on testing code

MATIS: fix what NULL means for l2gmap

conceptually, a NULL l2map is a full local to global map
petsc4py: support for MatCreateIS and add MATIS tests

petsc4py: add support for Mat{Set|Get}VecType

petsc4py: test Mat shift and scale methods

petsc4py: expose PCMatApply

added tests

MATPYTHON: implement MatHasOperation_Python

add tests

MatConvert_Basic: use matvecs if getrow is not implemented

Allow MatEqual to run the matvecs comparison if the implementation is not found
Add test for MATPYTHON

petsc4py: add support to run selected tests

For example, we can only run one unit test
python test/runtests.py -k test_mat_py.TestIdentity.testMatMat

MATPYTHON: add support for matrix matrix operations

petsc4py plex: test normalization
-Note that the plex only needs to be oriented because of the way it is set up (manually) in test_dmplex.py

plex metric: compute determinant when modifying metric

petsc4py plex: update error code in testAdapt

petsc4py plex: bindings for (Par)Mmg getters and setters

plex: DMPlex needs to be named before calling DM{View, Load}()

DMPlexCreateFromFile() takes mesh name as argument

petsc4py: Test state manipulation

petsc4py plex: update testAdapt

petsc4py plex: add testMetric

PETSC4PY: fix tests for single precision

Update H2 package