Standardize Module Client Interface Exports

[jackzampolin]

Updated per #1081

Currently modules export command line flags and LCD endpoints in an unstructured way. This leads to non standard command registration and can be confusing for users/devs. Modules offer three different interaction paths: cli-txs, cli-queries and lcd-routes.

Per #2575 we are moving each of the module's commands from being registered directly under the gaiacli query or gaiacli tx command to being registered under gaiacli query {{ .Module.Name }} and gaiacli tx {{ .Module.Name }}. Also per #1081 we are moving route registration from client/lcd to cmd/gaia/cmd/gaiacli in order to enable SDK devs to register routes from their own modules.

We should define a new interface for each module:

type ModuleCmds interface {
  GetQueryCmd() *cobra.Command
  GetTxCmd() *cobra.Command
  RegisterRoutes() *mux.Route
}

The interface will be implemented in a struct. The struct should contain all necessary pieces to build the query/tx commands and routes (codecs, storeKeys, etc...)

This would provide developers a standard way to expose their module functionality and would allow for a lot of cleanup in the cmd folder.

[alessio]

Seconded

[jackzampolin]

Closing this issue as addressed.