[webui] Fixed add reviewer to submitrequests
[backend] fix project wide hostlabel constraints type conversation
[backend] fix mergeconstraints for physical memory
[api] avoid double defintions of default repositories with the same name
[api] raise correct error when using same architecture multiple time for a repository (no crash)
[api] unbreak maintenance release request creation with patchinfos going to unlimited release targets
[backend] Fix handling of hostlabel constraint