OR-782 Split activitystream angular module in several files

Created activitystream/{directives.js|controllers.js|services.js}.
Also updated activitystream test files layout
OR-782 Use an isolate scope for the activitystream directive
Merge pull request #574 in OR/rse from ~MBAILLY/rse:OR-782-prepararation-work-for-activitystream-updates to master

* commit '6fa40057baa5c78bc1b4f5a91e2a6b691acf171e':
  OR-782 Use an isolate scope for the activitystream directive
  OR-782 Split activitystream angular module in several files