CORE+GUI: many usability fixes and one postgre compatibility fix 

CORE
- Fixed case when getting members count based on members status for PostgreSQL (+added test)

GUI
- display indirect members in tables with italic font
- indirect members can be set as "not checkable" to prevent
   remove action, which would fail on perun side (group members tab)
- Implemented MemberColumnProvider to simplify same table building
   in multiple callbacks
- clear search string after adding member to group
- added support for RichMember to CustomClickableCellWithAuthz
- added custom style support based on object and attribute for same cell
- Updated services tabs and forms to use ExtendedTextBox
  in order to handle cut/paste actions.
- Fixed KeyUpHandler for filter widget in TabMenu. Show suggestions
  only if not already shown, because key up/down reset selection.
- Added filtering for ext sources and vo ext sources, used when adding
- Allow multiple add vo/group/facility manager without closing the tab
- Suggestions when filtering groups takes ":" as whitespace so we
  can now filter also between subgroups in same table
  (e.g. "ncbr:kulhanek" is offered now if "kul" is in input).
- Added filtering on groups on Member's groups tab.
- Added filtering on groups on GroupAdmin's SelectGroup tab.
- Put "No resource available" in selectionbox on GroupSettings tab
  if group is not assigned to any resource (prevented switching to
  members settings)
- Better cross-site request exception message.
- Use entities names in result messages for add/remove member/manager
- Added filtering on groups, services and tags assigned to resource, facility owners and hosts.
- Redesign AddHosts tab to match CreateFacility wizard.
- Unified implementation of filterTable(), so oracle
  is never rebuild when filtering (should speed things up).
- Add link to facility detail from DestinationResult tab.
- Fixed formatting of UrlMaper
- Fixed URL of DestinationResults tab which prevented reopening
  on browser page refresh.