Add client configuration

[colin-axner]

I'd like to be able to call a CreateClient() function and pass in a configuration type to construct the client. A similar idea is used in our unit testing package on ibc-go

[colin-axner]

Looks like this is closed by #248! Thanks @boojamya, I'm currently working on writing a e2e test using this, so I appreciate the quick turnaround!

[boojamya]

Hey @colin-axner! No prob, but is this what you were asking for?

This allows the relayer to pass in create client options (only client trusting period in this PR). I thought you wanted to be able to pass in a a client_state.json from the chain.
EX:
gaiad tx ibc client create [path/to/client_state.json] [path/to/consensus_state.json]

This PR only adds the ability to do something like:
rly transact client src_chain_name dst_chain_name path_name --client-tp 508h

[colin-axner]

I primarily needed this to test client recovery proposals. The approach I'm going with is to set a really low trusting period (1 second), wait for the client to expire and then update it with a client with a regular trusting period.

It might be useful in the future to specify other fields like the trust level. I also wonder if the create client options should be more of an interface since there might be different configurations depending on the client you are creating. That's what I went with in the ibc-go testing package. We just do a switch on the client type. Though this functionality hasn't been useful to us yet since we mainly test our tendermint client in that package

[colin-axner]

Here's where I am using it cosmos/ibc-go#2130