Interactions overhaul

Mostly about getting interactions free from the concert.

* `rocon_interaction` related messages moved from `concert_msgs` -> `rocon_interaction_msgs`
* Interaction messages api simplified (no more horrid nesting dictionaries).
* `concert_msgs/ConcertInfo` -> `rocon_std_msgs/MasterInfo`

Brought to you by https://github.com/robotics-in-concert/rocon_concert/issues/188