* Add Initializer to the controller
The Initializer adds support for running any required initialization
steps when the controller is first started.
* Implement HCP Link initializer
The link initializer will create a Link resource if the
cloud configuration has been set.
* Simplify retry logic and testing
* Remove internal retry, replace with logging logic
* Implement In-Process gRPC for use by controller caching/indexing
This replaces the pipe base listener implementation we were previously using. The new style CAN avoid cloning resources which our controller caching/indexing is taking advantage of to not duplicate resource objects in memory.
To maintain safety for controllers and for them to be able to modify data they get back from the cache and the resource service, the client they are presented in their runtime will be wrapped with an autogenerated client which clones request and response messages as they pass through the client.
Another sizable change in this PR is to consolidate how server specific gRPC services get registered and managed. Before this was in a bunch of different methods and it was difficult to track down how gRPC services were registered. Now its all in one place.
* Fix race in tests
* Ensure the resource service is registered to the multiplexed handler for forwarding from client agents
* Expose peer streaming on the internal handler
Melissa Kam
Matt Keeler