Remove the ambiguity between OpenAPI spec and WorkerBridge's own API definition format

[afsalthaj]

Based on the feedback from @jdegoes , there exists a confusion in exposing the support of both open-api and worker-bridge's own format of API definition to the users.

Creating the ticket as part of review process that happened on #241

[afsalthaj]

Estimate 3.0, only once we decide what needs to be done

[afsalthaj]

I actually couldn't conclude on a solution to this yet.
I did give thoughts, but not able to decide. Probably we need some brainstorming here with details.

[vigoo]

With moving to have our own api definition format as part of app manifest, and having a separate functionality to export OpenAPI specs, I think we can close this