Feature/redesign helmholtzmatfree

Issue/feature addressed

Add HelmholtzMatFree implementation, unit tests, and also the profiler.

Proposed solution

Implementation

Tests

Suggested reviewers

Notes

The previous profiler merge request was closed and the contents are included here.

Sample command to run the profiler:

likwid-mpirun -hostfile ~/hostfile -nperdomain S:18 -m -g MEM_DP $PATH_TO_PROFILER/ProfilerBwdTrans -v -P Ntest=1000 -P order=5 $PATH_TO_MESH/hex-5.xml

Checklist

• Functions and classes, or changes to them, are documented.
• User guide/documentation is updated.
• Changelog is updated.
• Suitable tests added for new functionality.
• Contributed code is correctly formatted. (See the contributing guidelines).
• License added to any new files.
• No extraneous files have been added (e.g. compiler output or test data files).