[femutils] Added direct PETSc solver

[jojoasticot]

The following files were added:

• femutils/PETScDoFLinearSystem.cc
• femutils/PETScDoFLinearSystemFactory.axl
• modules/testlab/inputs/Test.petsc_direct.arc

To test the program, you type the following command:
./Testlab inputs/Test.petsc_direct.arc

You can also add petsc flags with the -A,petsc_flags="..." option

Example to run the test with matrix and vectors stored on GPU memory:
./Testlab -A,petsc_flags="-vec_type cuda -mat_type mpiaijcusparse" inputs/Test.petsc_direct.arc

Default -ksp_type is cg and default -pc_type is jacobi

[codecov]

Codecov Report

❌ Patch coverage is 89.54248% with 16 lines in your changes missing coverage. Please review.
✅ Project coverage is 69.41%. Comparing base (e97e5cd) to head (c016626).
⚠️ Report is 12 commits behind head on main.

Files with missing lines	Patch %	Lines
femutils/PETScDoFLinearSystem.cc	89.18%	12 Missing and 4 partials ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #316      +/-   ##
==========================================
+ Coverage   69.13%   69.41%   +0.28%     
==========================================
  Files         113      114       +1     
  Lines       14336    14482     +146     
  Branches     1960     1967       +7     
==========================================
+ Hits         9911    10053     +142     
- Misses       3978     3979       +1     
- Partials      447      450       +3     

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