Resolve "Magnetic-mechanic coupling with non-conforming interfaces in 3D"

Description

Non-conforming interfaces significantly increase RAM consumption and CPU time for some models. For more information see Testsuite!28.

Merge with Testsuite!28

TODO:

• Reduce NNZ during NCI creation
• Find a way to overwrite the old system matrix
• Build new matrix
• Replace the matrices
• Make everything thread save (currently multi core runs end in a segfault)
• Adapt the implementation so that the tests don't fail (non-linear etc.)

Check before assigning to a maintainer for review

• the history is clean
• code is well documented and understandable
• there is a testcase (in case of new functionality)
• every commit passes the pipeline

Maintainer checks before merge

• Review is approved, and all comments are resolved
• Check for Testsuite changes, if yes check
  • Testsuite merge request merges fast-forward
  • Testsuite-submodule SHA of every CFS commit references a commit in Testsuite Merge Request
  • Testsuite-submodule SHA of last CFS commit points to HEAD of corresponding Testsuite branch
• Pipeline passes for every commit
  • all stable tests pass
  • testsuite tests run
  • new tests are actually running (e.g. check if they appear on CDash)

Closes #25