Mesh tutorial and documentation changes and some refactoring

See merge request !92

The new value is not correct, it breaks e.g. ParallelFor2D and
ParallelFor3D (for which we had disabled tests by mistake). We need to
separate the max values for x, y and z axes, see the linked Gitlab
issue.

This reverts the commit 37632fd9

The Experimental directory does not make much sense - there is a lot of
experimental or just unused code in TNL, e.g. Images or Operators.

- tests moved to the main UnitTests directory
- added missing inclusion of the Algorithms tests directory to
  CMakeLists.txt

It is an implementation of a specific solver, not part of the general
(header-only) library. If there are some useful generic templates (like
operators etc.), they need to be refactored into the generic interface.

This is more suitable location because the build config tags are used
only by the GridTypeResolver and MeshTypeResolver classes.

Refactoring: renamed TypeResolver.h to resolveMeshType.h and loadDistributedMesh.h to resolveDistributedMeshType.h

It was unused, untested and unnecessarily complicated. We will deal with
entity orientations when it is actually needed.

I think that the implementation based on storing the whole permutations
of subentity indices is not appropriate anyway - it induces huge memory
consumption, while e.g. for faces we are interested only in the
orientation of the outward normal vector with respect to the two
adjacent cells, which can be stored as one bit per face-cell pair, or it
can be deduced from the entity indices if we enforce a suitable
convention (e.g. all normal vectors could be outward with respect to the
adjacent cell with the smallest index). I think OpenFOAM uses a similar
convention for normal vectors. As for the orientation of edges in 3D, I
have no idea where it could be useful...

To/matrices adaptive csr

See merge request !91