Reimplement headercheck using target and file sets information

The following discussion from !1512 (merged) should be addressed:

• @santiago.ospina started a discussion: (+4 comments)

  I just read a bit of the headercheck code and some of the discussion in #212. This feature is indeed useful but this implementation has just too many assumptions and very little to no documentation. Adding dune_default_include_directories deepens these assumptions even further. In my opinion this should be re-implemented based on the FILE_SETS of a target. That would remove most of these assumptions. But since that's a CMake 2.23 feature we would have to wait a little bit for that. For now, I guess this is OK in order to advance in the CMake modernization (like needed in extensions/dune-alugrid!192 (merged))

added buildsystem label