Using volume primitives in Watchpoint if available

[boris-martin]

Main changes of this PR

If a Watchpoint watches a point inside the domain, it interpolates on the cell instead of looking for a projection on a boundary element. If there is none (no 2D triangle or no 3D tetra), fall-back to previous behavior, * à la* Nearest-Projection

Motivation and additional information

More accurate watchpoint when used in volumetric coupling

Author's checklist

• I added a changelog file with make changelog if there are user-observable changes since the last release.
• I ran make format to ensure everything is formatted correctly.
• I sticked to C++14 features.
• I sticked to CMake version 3.16.3.
• I squashed / am about to squash all commits that should be seen as one.

Reviewers' checklist

• Does the changelog entry make sense? Is it formatted correctly?
• Do you understand the code changes?

[fsimonis]

Could you add a parallel test where rank 1 finds a tetrahedron and rank 0 finds a triangle?

The coordination and ownership has to be correct in parallel cases too and we should explicitly test for that.