First commit of the matchmaker APIs

This is a wip translation of the matchmaker APIs into avro.

Autogenerated docs are here: http://cassiedoll.github.io/matchmaker-staging.html
This was initially a `string` to allow other value in the future, for example suspected features not yet confirmed, or expected future symptoms. I'm not sure if this is a good idea, or if keeping things simple with a `boolean` is enough.