Separated the user synchronization from group synchronization

[vyskocilpavel]

• Added method for get all user attributes
• Rewrite the group synchronizations
• Added method for get RichUser with all attributes
• Added method for convert RichUser to RichUser with all attributes
• Added method for create User from Candidate
• Extend JSONP serializer to ignor usersSubjects property
• Added method for set UserExtSource attribute in nested transaction
• Added new method getUsersSubjects() to all ExtSources
• Separated the user synchronization from group synchronization
  • Users are now synchronizated independantly on group synchronization.
  • All synchronized attributes are stored as UserExtSource attribute for the correct ExtSource.
  • Every synchronizated UserExtSource have the priority.
  • User attributes are selected from UserExtSource with the highest priority.
  • If user is not PerunUser during the group synchronization, group synchronization start the user synchronization

[balcirakpeter]

This pull request will be split into more smaller pull requests. We can close this one when the smaller pull requests will be merged.

[balcirakpeter]

Closing the PR. We would have to rewrite it from scratch anyway. Moreover, we are not planning to continue with user synchronizations right now.