BE - 1: Update all endpoints that MODIFY active/queue

[Ron-Madan]

In order to make sure that each location's "lastUpdateTime" property is maintained, we must slightly modify all endpoints that modify the active or queue collection. In particular, each of these endpoints should set the timestamp on the location document. See firestore for intuition.

These endpoints include [double check]:

• resetCourts
• joinQueue
• leaveQueue