Merge branch 'cleanup/doxygen_mainbranch' into 'master'

Cleanup doxygen

Closes #835

See merge request !1964

(cherry picked from commit 73cbb603)

8a37683f [doxygen] Temporarily remove copydoc and copydetails with file paths. Copydoc...
9064179e [doxygen] Correct copydocs without backslash.
1068eb21 [doxygen] Remove copydoc of something that does not exist.
7a26b0ff [doxygen] Fix link to parameterlist.txt.
06de8c79 [doxygen] Fix parameters which are not documented or do not exist.
2c465c69 Increase DOT_GRAPH_MAX_NODES. Default value of 50 is sometimes exceeded by Dumux.
de8d9f48 Use the doxygen command \deprecated nowhere. Deprecated stuff is already in...
c9c87ff0 [doxygen] Improve ingroups.
44a43db1 [docu] Correct dimWorld.
80aa104a [doxygen] Changes to stop things appearing as description of Dumux namespace.
ba332bb6 [doxygen] Add comment about nicer file names for the website.
ed560ce0 [doxygen][cleanup] We don't use the Dune depreaceted macro anymore