#1864 added support for searching and downloading descriptions from public registries. (apis.guru, hardcoded MS Graph).

We should add support for additional registries to broaden the set of results.

One such candidate could be apigee registry which is a solution that can be hosted and accessed privately (internal APIs). It also seems to be what google uses publicly.

https://developers.google.com/discovery/v1/reference/apis/list
https://apigee.github.io/registry/
https://apigee.github.io/registry/api.html#google.cloud.apigeeregistry.v1.ListApisRequest

We should:

• identify other candidates
• break down each selected candidate into separate issues
• add support for each of them.