KMS-5027 #comment Define spinner DOM target  #time 4h

Dual screen adds transitions to mwEMbedPlayer div that holds the
spinner DIV so it moves when transitioned, so add ability to define
spinner DOM target and attach it to elements that don’t transition.
Merge pull request #1266 from kaltura/KMS-5027

KMS-5027 #comment Define spinner DOM target  #time 4h