playerendpoint: Forward EOS event to main pipeline

Change-Id: If09ac51e4de7f20890b3659891b51d20e455c64c
httpendpoint: Raise eos event when it is received from the player

Change-Id: I697f94af3c428ddbd0428a88a42e842d5512afce
httpendpoint: Add "is-live" property

This property indicates if the element should be stopped when it receives
a eos or wait until it is released.

Change-Id: I7a88fe63670321174d3368552770ed2dd302f6a4