As a user, I want to be able to move an event to another calendar

As a user, when I edit an event, I want to be able to change the event calendar of event I've organized.

Criteria

[x] Calendar field should be enabled when editing event
[x] When saving the event, attendee should not be notified due to modification of the calendar as it is not an event scheduling information
[x] When saving the event, the event calendar change should be pushed to every browser that displays the calendar (including user's views and people user has shared calendar with)
[x] Calendar field should only display calendar owned by the current user (see note)

If user has write permission on another user calendar, this calendar should not be displayed in calendar list. As the event organizer is the calendar owner, if user moves an event to someone else's calendar, the organizer needs to be changed. Changing the organizer means rescheduling the event, this case will be addressed in further issue.