[cleanup] Remove configure flag --with-alugrid-libdir.

This flag is deprecated for several years and was
no longer working.
[cleanup] Remove trailing spaces and tabs in alugrid.m4.
[cleanup] Use ALUGrid in gmeshtest instead of ALUSimplexGrid.

ALUSimplexGrid was deprecated in Dune 2.3.
[cleanup][UG] Remove deprecated boundaryId().
[cleanup][ALUGrid] Remove support for aluids !Tetraeder, !Hexaeder

Use !Tetrahedra, !Hexahedra instead.
The old aluids were deprecated in 2006.
[cleanup] Remove deprecated methods from PersistenConatiner*
[cleanup] Use ALUGrid in amirameshtest instead of ALU(Simplex,Cube)Grid.

This change is untested due to lack of AmiraMesh.
[cleanup] Remove deprecated ALUSimplexGrid, ALUCubeGrid, ALUConformingGrid
[cleanup] Remove spcializations of ALU*Grid.

Remove forward declarations, capabilities, PersistentContainer.
If alugrid/(2,3)d/capabilites.hh is not part of the interface,
the transition header can be removed.
[cleanup] Adjust documentation to follow ALU*Grid to ALUGrid.