Merge branch 'cleanup/doxygen_mainbranch' into 'master'

Cleanup doxygen

Closes #835 (closed)

See merge request !1964 (merged)

(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