Common contact role form & page permission fixes
As I accidently merged !257 (merged) too early, I opened this MR to create a shared component for contact role assignment.
Goal of this MR:
- add a form component for the assignment of contacts and roles to devices / platforms / configurations
- fix issue with error messages "you're not allowed to edit xyz" when reloading a page #279 (closed)
Fixes also #279 (closed)
Edited by Marc Hanisch