Remove dependency on group name in VŠUP services
Created by: zlamalp
- Type of relation (student/employee/teacher/external) is not taken from a group name anymore. It's now attribute of Resource. This allows us to rename groups.
- It's now used for KOS (student/teacher) and WEB services (manages only external workers).
- Fixed deletion in web services (allow empty set - delete all).
- Rewritten all conditions for defined values from (def val) ? val : ' ' to val1 || ' ' (KOS,RAV,TRITIUS,WEB).