CLI: help command output should be more readable

It is starting to shape very nicely.
I think it would help to maybe indent subitems.

E.g.:

coopr (http://localhost:55054)> help
COOPR_HOST=localhost

Available commands:
help: Prints this helper text
connect to <host> as <user> <tenant> [using port <port>] [with ssl <enabled/disabled>]: Connects to a Coopr instance
exit: Exits the cli

delete

• delete template <name>: Deletes a cluster template

• delete hardware type <name>: Deletes a hardware type

• delete image type <name>: Deletes an image type

• delete provider <name>: Deletes a provider

• delete service <name>: Deletes a service

get

• get template <name>: Gets the cluster template

• get hardware type <name>: Gets the hardware type

• get image type <name>: Gets the image type

• get provider <name>: Gets the provider

• get service <name>: Gets the service

• get cluster <cluster-id>: Gets the cluster

• get cluster-config <cluster-id>: Gets the cluster config

• get cluster-status <cluster-id>: Gets the cluster status

list

• list templates: Lists all cluster templates

• list hardware types: Lists all cluster hardware types

• list image types: Lists all image types

• list providers: Lists all providers

• list services: Lists all services

• list clusters: Lists all clusters

• list services <cluster-id>: Lists all cluster services

[...]