Moved role constraints into model and removed edit deployment

(cherry picked from commit b6becfa8eb113ad5b4a7826192e2d18342b6c532)
Merge pull request #190 from vuntz/release/roxy/master

Moved role constraints into model and removed edit deployment
Removed the single assignment block from constraints
Merge pull request #191 from tboerger/feature/roxy/fix-constraints

Removed the single assignment block from constraints