Addition: Profiling ghost creation timings on fractally refined meshes.

[jmark]

Describe your changes here:

This PR adds a new benchmarking example application to t8code which, among other stuff, measures the runtime contribution of ghost layer creation. This program is derived from an already existing benchmark but is was much simplified and tailored for benchmarking ghost layer creation. See NOTES in the source code for detailed info.

This PR is a result of a review request regarding the JOSS paper submission: openjournals/joss-reviews#6887

All these boxes must be checked by the reviewers before merging the pull request:

As a reviewer please read through all the code lines and make sure that the code is fully understood, bug free, well-documented and well-structured.

General

• The reviewer executed the new code features at least once and checked the results manually

• The code follows the t8code coding guidelines

• New source/header files are properly added to the Makefiles

• The code is well documented

• All function declarations, structs/classes and their members have a proper doxygen documentation

• All new algorithms and data structures are sufficiently optimal in terms of memory and runtime (If this should be merged, but there is still potential for optimization, create a new issue)

Tests

• The code is covered in an existing or new test case using Google Test

Github action

• The code compiles without warning in debugging and release mode, with and without MPI (this should be executed automatically in a github action)

• All tests pass (in various configurations, this should be executed automatically in a github action)

  If the Pull request introduces code that is not covered by the github action (for example coupling with a new library):

  • Should this use case be added to the github action?
  • If not, does the specific use case compile and all tests pass (check manually)

Scripts and Wiki

• If a new directory with source-files is added, it must be covered by the script/find_all_source_files.scp to check the indentation of these files.
• If this PR introduces a new feature, it must be covered in an example/tutorial and a Wiki article.

License

• The author added a BSD statement to doc/ (or already has one)

[jmark]

@Prasanna-Ponnusamy Do you need any further input in reviewing this PR?