Remove unused directories / readmes

70-oeffentlich/.gitignore

-*
-!readme.md
-!.gitignore

70-oeffentlich/readme.md

-# /70-oeffentlich
-
-This directory is intended as a repository for exam files for which we have 
-the explicit permission to share them publicly in digital form.    
-As we do not have any such material by the time of writing this, no further
-design of the directory structure has been made and integration into the 
-software solution is not done yet.

80-inoffiziell/.gitignore

-*
-!readme.md
-!.gitignore

80-inoffiziell/readme.md

-# /80-inoffiziell
-
-What you see here is an empty directory. It absolutely does not contain any
-material we were not supposed to have or were offered to us through slightly
-dubious channels. 
-This is because we play by the rules and do not accept material that wasn't
-handed to us by the original author or people authorized by them.
-
-