OBMFULL-6099 HelperService can return a set of rights.

Given a collection of logins, the HelperService can return the rights the holder
of the AccessToken has on these calendars. In addition, the HelperDao now throws
an exception.
OBMFULL-6099 Adds handling of access rights.
OBMFULL-6099 Strong typing for calendar rights.

Use a CalendarRights object instead of a map.
OBMFULL-6099 findAttendeesWithEmail -> filterAttendeesWithEmail