SOAP-1339: Refactoring OltuOAuth2ClientFacade as it was getting bigger and bigger
SOAP-1339: Added combo box to select different OAuth2 flows from the GUI, also added the required parameters in OAuth2Profile
SOAP-1339: Implicit flow works now
SOAP-1339: Units tests for implicit grant flow and refactored the unit tests for OltuOAuth2ClientFacade