Remove validation concept from esf
Adapt administration to removed validation concept
Adapt user view of esf to the removed validation concept and rework esf edit form
Replace tab view in esf with two buttuns which provide the same functionality; also fix caching issues of user details, fixes #23
Remove obsolete method of studypath manager and make names of the remaining ones more clear
Merge: Remove validation concept and rework esf view, fixes #10

* issue10:
  Replace tab view in esf with two buttuns which provide the same functionality; also fix caching issues of user details, fixes #23
  Adapt user view of esf to the removed validation concept and rework esf edit form
  Adapt administration to removed validation concept
  Remove validation concept from esf