[Metadata] Convey effective type from REST layer

[nguerrera]

Currently the getEffectiveType happens in the openapi emitter and another REST-based emitter would need to replicate this. It might be nicer to convey this in the data returned from the REST layer about the routes than to require an emitter to call it on their own.

[nguerrera]

This won't work. You need to apply getEffectiveType recursively so we can't just do it on the root types and put those in the return objects from REST layer. What we should do instead is make a helper in REST layer and maybe put it in/next to MetadataInfo. This can be implemented in #1070 and documented in #1083

[nguerrera]

Closing as covered by #1070 and #1083, adding notes to each.