[Feature Request] Better help strings

[bergundy]

Some of the help strings the CLI prints out today are confusing and unhelpful.

• [ ] temporal server

Today's output:

NAME:
   temporal server - Commands for managing the Temporal Server.

USAGE:
   Server commands allow you to start and manage the [Temporal Server](/concepts/what-is-the-temporal-server) from the command line.

   Currently, `cli` server functionality extends to starting the Server.

   Server commands follow this syntax:
   `temporal server COMMAND`
Suggestion:

NAME:
   temporal server - Start a [Temporal Server](/concepts/what-is-the-temporal-server).

USAGE:
   Use the subcommands such as `start-dev` to start the server:
   `temporal server COMMAND`* [ ] `temporal server start-dev`

Today's output:

NAME:
   temporal server start-dev - Start Temporal development server.

USAGE:
   The temporal server start-dev command starts the Temporal Server on localhost:7233.
   The results of any command run on the Server can be viewed at http://localhost:7233.

Suggestion:

NAME:
   temporal server start-dev - Start a Temporal development server.

USAGE:
   `temporal server start-dev [OPTIONS]`We need to review every single command so I decided to stop here but this is critical to fix before 1.0.0.