Fix bug #1661857 (switch from using meta feed to the new allcalendars feed)

- add more properties to Calendars: selfUrl, editUrl, eventsUrl and deleted
- add CalendarsEntity and associated iterator
- cleaup interfaces definition for Calendars / Events columns by factorising  Sync and Account columns

Change-Id: I730e9d377316d458f7d225ce85966c7048ad26a9