Cosmos-sdk: Add gaiacli config command & config file

[rigelrozanski]

One of the most valuable features for cleanup phase is add a gaiacli config command. Ultimately this is where the source-of-trust will be initialized for light client proofs, but also in the meanwhile we can use it to set a bunch of the redundant parameters, and then remove (or hide) them from the majority of gaiacli commands.

Flags which I think can be stuffed in the gaiacli init are:

      --chain-id string   
      --height int        
      --ledger            
      --node string     
      --trust-node        
Global Flags:
      --encoding string   
      --home string       
      --output string    
      --trace             

[jackzampolin]

I think this would be GREAT and really help avoid large commands. I don't know if we should put --height in there, but the others are great. We could pull the default --chain-id out of the ~/.gaiad/config/genesis.json file right?

Another thing I've noticed is that --output isn't respected by many of the commands that return JSON.

Can you explain a bit more Ultimately this is where the source-of-trust will be initialized for light client proofs?

[rigelrozanski]

We could pull the default --chain-id out of the ~/.gaiad/config/genesis.json file right?

don't see why not

Can you explain a bit more Ultimately this is where the source-of-trust will be initialized for light client proofs?

it's exactly that - the light client needs to start from some source of truth, we need a command to initiate that source of truth which the user of the light client must verify through other means (chat with a friend, hashes into bitcoin etc)

[jackzampolin]

Well the issue with reading from there is that its not the root folder for gaiacli and we don't want to add a gaiad "dependency" on the CLI. They should ideally be completely independent, right?

So basically we would want to persist the --chain-id and the --node.

[mslipper]

I can take this guy.

[jackzampolin]

Awesome @mslipper