SchemaBundle: remove use of Router and Templating Service in EmbeddedBroadcastService

[mreyk]

To avoid circular dependencies if this service is used in other services (twig services for example), remove the user of Router and Templating Service in EmbeddedBroadcastService.
This affects each Controller that uses the canUserPlayMultimediaObject function
https://github.com/campusdomar/PuMuKIT2/blob/master/src/Pumukit/SchemaBundle/Services/EmbeddedBroadcastService.php#L255
and the response it gives to the controllers.