Replacement of fwk, tbox, tboxVtk by amfe

• amfe is now used as a submodule (as in dartflo).
  • fwk, tbox et tboxVtk have been removed from the repository and from the README.md file.
  • Missing "_Kim2CLEAN" code has been added to the katoptron module.
  • The CMakeLists.txt have been adapted (from those of dartflo).
• Copyright date has been updated.
• CMake files (in the CMake/ folder) have been cleaned.
• Kim has been removed from the code owners so that we can modify his code without waiting for his approval.
• The tolerance on CM for the lift3 test case of flow has been increased to 2.5% instead of 1% so that it works with a recent version of Gmsh.

Next steps:

• create a separate repo for Kim's code depending on Trilinos (katoptron, tlnos) and maybe mirrors and params,
• create a separate repo for the other solvers (heat, waves),
• replace waves by amfe in PFEM,
• replace flow by dartflo in CUPyDO,
• remove all solvers from the master branch of this repo.
• freeze (archive) this repo and update README.md with links to the new repos.