[LMS-1949] improved UI for script registration/edition and assignment;

...lication/ui/property_type/PropertyTypeAssignmentForm.java

...plication/ui/property_type/ScriptTypeSelectionWidget.java

...application/ui/script/AbstractScriptEditRegisterForm.java

...ient/web/client/application/ui/script/ScriptEditForm.java

.../client/application/ui/script/ScriptRegistrationForm.java

.../generic/client/web/client/application/util/GWTUtils.java

...msx/cisd/openbis/generic/server/business/bo/ScriptBO.java

...msx/cisd/openbis/generic/shared/basic/dto/ScriptType.java

...ch/systemsx/cisd/openbis/generic/shared/dto/ScriptPE.java

...cisd/openbis/generic/server/business/bo/ScriptBOTest.java

...c/server/dataaccess/db/AbstractDAOWithoutContextTest.java

...d/openbis/generic/server/dataaccess/db/ScriptDAOTest.java