Add refresh event `POST /refresh/:roomId`

[alekseykulikov]

[ ] use similar authentication process: #4
[ ] add refresh event to client
[ ] on activecell: post request to porchetta after data reload

[alekseykulikov]

@adamrneary can you say, we need this functionality now, or it's for future?

[adamrneary]

tough to say. lots of things on our plates with high urgency. i think some of the striker tasks are more urgent, but if there's a huge cost to switching, let's try to wrap up porchetta and shotgun this week.