GitLab

also replace *Datastore with Datastore

Adds "ipfs config" command designed in git style.
See specific config's values with:

        $ipfs config datastore.path
        ~/.go-ipfs/datastore

Assign a new value with:

        $ipfs config datastore.path ~/.go-ipfs/datastore

Open the config file in your default $EDITOR:

        ipfs config edit

link errors left:
- protocol buffers output is not lint-friendly