Automatically expose documented API based on the defined Operations

[Martinsos]

We could use Swagger or Openapi for this, or something similar!

It would also make sense to first work more on allowing users to define which API is public, should not change, allow them to customize it, ... , before we let them expose it like this.

[Martinsos]

Btw Rails has an option to print all the routes, maybe that is good first start.

Btw this is also about us promising to not change how routes work without it being a breaking change.

[Martinsos]

Related to #268

[Martinsos]

@breadchris expressed interest in this.

[Martinsos]

NOTE: We are now using superjson for serializing / deserializing RPC calls, so if we will be exposing them as an API, we need to look into making that work with superjson.

[Martinsos]

From some feedback we got, this would help with allowing building mobile and other clients that can then use existing Wasp's backend.

[Martinsos]

Btw they could create their own API by writing their own api declarations and reusing the logic they use in Operations, but that is quite some work and would be much nicer to just be able to get that API for free.