Set up a new console endpoint to eventually serve both useModules and useSchema console use cases

[deniseli]

Currently, we have two separate endpoints, one on the console service and one on the controller service, that both provide most of the data we need. We can't standardize to just one of those two because they're each missing data that only the other contains. We should just build a new endpoint that actually includes everything, formatted correctly, so we don't need to do this going forward.

Also, the new one needs to include the builtin module.

[wesbillman]

We'll probably want a dedicated StreamModules rpc in console service so we can live update the tree and the rest of the app as needed.

That might look something like this, and would replace PullSchema (which lives on the controller service now).

rpc StreamModules(StreamModulesRequest) returns (stream StreamModulesResponse);

The response here would be lighter weight than the PullSchema since we only really need enough data to build the module tree and provide data to dedicated decl pages. This will also let us control what the Module looks like to the frontend.