Add some form of connection manager for the client about http2-grpc-haskell HOT 1 OPEN

The solution to this is largely specified by the gRPC design. The state machine tracking this information for a channel is specified in https://grpc.github.io/grpc/core/md_doc_connectivity-semantics-and-api.html.

gRPC has a "channel", which is a virtual connection to the an endpoint. An endpoint may be served by many servers. Channels have "subchannels", which are logical connections to a server. The subchannel maintains the actual TCP connection. If a channel dies, there is standard logic to either choose another subchannel, or to repair the connection.

When gRPC does reconnect, it uses an exponential backoff aproach described here: https://grpc.github.io/grpc/core/md_doc_connection-backoff.html.

from http2-grpc-haskell.