Writing a gRPC Client for tendermint/iavl

[martyall]

It seems like they are working on the protobuf files and writing the server on the tendermint side.

We can track the issue PR on the tendermint side here https://github.com/tendermint/iavl/pull/184

Here is an example using protolens and gRPC in haskell https://github.com/f-o-a-m/hs-trillian/tree/master/hs-trillian-log

we need to

• [ ] add a separate stack project in this repo for the client library (with tests)
• [ ] add an interpreter for the RawStore effect
• [ ] integrate with the nameservice app

[martyall]

depends on #145