gRPC custom client/server certificates & grpc channel options

Is your feature request related to a problem? Please describe.
Can't use insomnia for gRPC because we authenticate to our gRPC services using a custom PKI, and need to pass particular additional [options]( to the client builder (grpc.ssl_target_name_override, grpc.keepalive_time_ms,...).
We are stuck to BloomRPC because of this, and bloom doesn't work super well (lack of ergonomics, environment management, and diverse bugs).

Describe the solution you'd like
Being able to configure, ideally by workspace with overrides per environment, the set of CA key, client certificate, client key and [additional options](

This is where this should hit in the code:


becoming in effect:


(note that it looks like gRPC Core does not receive the options in the same way if they are integers or strings, so this may matter. I'd be very happy with providing these as a JSON, similarly to what's done with the environments.)