Preferred primary unix group names final

- new behavior of setting required attributes for member and resource
- new unixGID workflow (with preferredUnixGroupName-namespace:*)

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NEED TO DO AFTER MERGE THIS PULL REQUEST:

 1] CREATE NEW ATTR_DEFs:
  - UF:def:basicDefaultGID (R: anyone, W: FACILITY)
  - U:def:preferredUnixGroupName-namespace:*
   (*=cerit,egi-ui,einfra,sitola,storage) (R: anyone, W: SELF)
  - UF:virt:defaultUnixGID (R: anyone, W: FACILITY)
  - UF:virt:preferredUnixGroupName (R: anyone, W:SELF)

 2] COPY value in DB
  - from def:defaultUnixGID (user_facility_attrs) to
   def:basicDefaultGID
  - use this sql:
   "insert into user_facility_attr_values
   (user_id, facility_id, attr_id, attr_value, created_at,
   created_by, modified_at, modified_by, status, attr_value_text,
   created_by_uid, modified_by_uid)
   select user_id, facility_id, X as attr_id, attr_value,
   created_at, created_by, modified_at, modified_by, status,
   attr_value_text, created_by_uid, modified_by_uid
   from user_facility_attr_values
   where attr_id=Y"
    - where X = id of UF:def:basicDefaultGID attr,
     and Y = id of UF:def:defaultUnixGID attr

  3] REMOVE attr value in DB
   - for attr UF:def:defaultUnixGID by sql:
    "delete from user_facility_attr_values where attr_id=X"
     - where X = id of UF:def:defaultUnixGID attr

  4] INCREASE DB-version

  5] ADD THESE info to the changelog and dbchangelog