Provide metadata for roomService's createRoom #24
Description
When a room (no longer) exists, the metadata is lost.
Currently, the only way is to draw (modify gameState.tileAttributes) and use saveRoomMetadata().
- One thing is to investigate room existence indefinitely (storing meta data with it)
- The other thing is to provide a "package": map/overlay image and metadata in JSON format to set up and host a room properly.