adopt gh gist subcommands for lpaste CLI

[pszemraj]

update/adopt naming convention for subcommands (that are relevant/supported already) on the cli to make things easier to remember:

(misc) ➜  ~ gh gist --help
Work with GitHub gists.

USAGE
  gh gist <command> [flags]

AVAILABLE COMMANDS
  clone:         Clone a gist locally
  create:        Create a new gist
  delete:        Delete a gist
  edit:          Edit one of your gists
  list:          List your gists
  rename:        Rename a file in a gist
  view:          View a gist

INHERITED FLAGS
  --help   Show help for command

ARGUMENTS
  A gist can be supplied as argument in either of the following formats:
  - by ID, e.g. 5b0e0062eb8e9654adad7bb1d81cc75f
  - by URL, e.g. "https://gist.github.com/OWNER/5b0e0062eb8e9654adad7bb1d81cc75f"

LEARN MORE
  Use `gh <command> <subcommand> --help` for more information about a command.