AutoCLI app command generation

[aaronc]

Add an auto-cli method to generate a full client from an app based on the module options and custom commands from #13282.

For now, this full client will necessarily be less complete than the current CLI. Over time we will fill in the missing pieces.

[aaronc]

One thing I'm trying to figure out when combining autocli and existing *cobra.Command's is how to specify the gRPC endpoint.

The current --node flag only points to the tendermint RPC endpoint and when gRPC is used, we just route it through tendermint ABCI query which is pretty inefficient. autocli on the other hand attempts to be gRPC native and could work without tendermint RPC.

I propose we add a flag --grpc or --grpc-endpoint which both the existing commands and autocli can use instead of --node if it's specific. And then autocli could fallback to ABCI query if only --node is specified.

How does that sound?