Merge branch 'remove-deprecated-std-final-hh' into 'master'

[std/final.hh] Remove, deprecated in 2.6.

See merge request !481

dune/common/std/CMakeLists.txt

 install(
   FILES
   apply.hh
-  final.hh
   noexcept.hh
   make_array.hh
   memory.hh

dune/common/std/final.hh

-#ifndef DUNE_COMMON_STD_FINAL_HH
-#define DUNE_COMMON_STD_FINAL_HH
-
-#warning The header dune/common/std/final.hh is deprecated. Remove the include and use "final".
-
-#define DUNE_FINAL final
-
-#endif   // DUNE_COMMON_STD_FINAL_HH