WUI: Allow to set correctly GWT and mvn:gwt plugin versions

- We now have same GWT and mvn:gwt plugin version across whole project.
- Each module can override it in properties tag in pom.xml.
WUI: major updated to Registrar

- All app form data are retrieved in one big callback.

- Now display also VO extension and group forms.

- Support for COMBOBOX form item.

- EMAIL item has correct styles and changes
  selection on typing (when value is pre-filled).
- EMAIL offer selection even on single value pre-fill.

- When SELECTIONBOX and COMBOBOX can be empty (value not required)
  add custom "--- Not selected ---" option.

- Backported fix for identity consolidator link (encode query string twice).

- Show modal dialog when similar users were found with selection
  of identity to join into (cert or IDP).

- Fixed style for PASSWORD input field.