[PBI] Simplify Service Discovery Process

[ladatz]

Description

Today, for an application to be a provider, it must implement the Provider interface and have a grpc endpoint to communicate on. This can be a lot of code required for an application that only wishes to expose an endpoint. Issue #117 is a great example of this. It would be better if Service Discovery had less requirements on a provider. Providers and Consuming applications should only need to call Chariott APIs, not implement any logic to be used.

Acceptance criteria

• "Discover" is a simple API call
• "Providers" are not required to implement an interface