Investigate using gRPC for all queries

[plafer]

I suggest we remove the proven_*() methods from ChainEndpoint and ChainHandle, and change the provable query_*() functions as follows:

I think it makes sense. A note though that the simple query_ APIs are generally (*) gRPC, the proven_ perform abci_query (RPC to tendermint who does app abci_query). When we first implemented the proven_ APIs there was no support for proofs in gRPC. But now there is. Maybe we should then:

• (*) change all query_.. for application state to use gRPC (we also have query_.. methods that retrieve blockchain info, i.e. they will stay RPCs to tendermint)
• change all proven_... to use the gRPC

wrt to query height, if you look at the gRPC request proto defs they do not contain the height at which the query should be done. This is "hidden" in the gRPC metadata. For and example on how this is done with gRPC you can take a look at https://github.com/informalsystems/ibc-rs/blob/c5c89dc82b1466101066e69d1228cda439da1d4b/relayer/src/chain/cosmos.rs#L931-L937

Also I don't know if there is a way to make a gRPC request and specify that there shouldn't be any proof included. If that's the case, we should look at performance differences between abci queries without proof and gRCP (with proof always??), especially if the APIs used by the packet relaying are affected.

Originally posted by @ancazamfir in #2200 (comment)

[plafer]

Closed as duplicate of #1088.