Fix all member_resource and resource quota modules

- add holders to exceptions (where it is possible)
- add attribute to exceptions (where missing)
- fix compare_to conditions for big decimal from "==-1" to "<0"
Fix possible collidation of userExtSource logins

- only for extSource type 'IDP'
- now every login in userExtSource type of IDP is unique
- add some notNull testing to method addUserExtSource in entry
- add new method for geting all userExtSources by extLogin and extType
- add simple test
Merge pull request #359 from stavamichal/fixPossibleCollidationOfLoginsInUserExtSourcesTypeIDP

Fix possible collidation of userExtSource logins
Merge pull request #357 from stavamichal/fix_quota_modules

Fix all member_resource and resource quota modules