Project: mesos
Issue MESOS-5404: Allow `Task` to be authorized.
As we need to be able to authorize `Tasks` (e.g., for deciding whether to include them in the /state endpoint when applying authorization based filtering) we need to expose it to the authorizer. Secondly we also need to include some additional information (`user` and `Env variables`) in order to provide the authorizer with meaning information.
Story points: 3