Starport add should have subcommands

[faddat]

Feature:

Starport add should tell the user what things they can add

[faddat]

This is kinda-sorta helped in #236

So starport now tells the user what they can add, however it might be better to make this into a subcommand, those are easily listed in cobra and might look more like:

❯ docker container

Usage:  docker container COMMAND

Manage containers

Commands:
  attach      Attach local standard input, output, and error streams to a running container
  commit      Create a new image from a container's changes
  cp          Copy files/folders between a container and the local filesystem
  create      Create a new container
  diff        Inspect changes to files or directories on a container's filesystem
  exec        Run a command in a running container
  export      Export a container's filesystem as a tar archive
  inspect     Display detailed information on one or more containers
  kill        Kill one or more running containers
  logs        Fetch the logs of a container
  ls          List containers
  pause       Pause all processes within one or more containers
  port        List port mappings or a specific mapping for the container
  prune       Remove all stopped containers
  rename      Rename a container
  restart     Restart one or more containers
  rm          Remove one or more containers
  run         Run a command in a new container
  start       Start one or more stopped containers
  stats       Display a live stream of container(s) resource usage statistics
  stop        Stop one or more running containers
  top         Display the running processes of a container
  unpause     Unpause all processes within one or more containers
  update      Update configuration of one or more containers
  wait        Block until one or more containers stop, then print their exit codes

Run 'docker container COMMAND --help' for more information on a command.

Which is more like what I had in mind when I created this issue.

Also might be notable that it isn't currently possible to offer --help for arguments; only subcommands.

[fadeev]

Good catch, Jacob! We're planning on moving to starport module import foo, so we'd probably have a ...module list subcommand to list everything, perhaps, with a brief description of each module.

[fadeev]

We no longer have add command and the whole CLI experience is due for a redesign.