Reformat plugin's vendor position and add version on --help

[ulyssessouza]

Checks the fourth box on: #1661

- What I did

• Refactor plugins' vendor location on --help by relocating it at the end of the short description
• Add ", " to command vendor

- How I did it
By changing the usageTemplate in cli/cobra.go to replace the information and decorating the command with a '*' when it's a plugin's first level command

- How to verify it

• Install a plugin (or make your configuration point to one)
• Execute docker help and check that the plugins' first level commands have now a '*' and it's vendor as short description suffix

- Description for the changelog
Reformated plugins' first level command description on --help by replacing and vendor and adding version

- A picture of a cute animal (not mandatory but encouraged)

[codecov-io]

Codecov Report

Merging #1675 into master will increase coverage by 0.07%.
The diff coverage is 63.15%.

@@            Coverage Diff             @@
##           master    #1675      +/-   ##
==========================================
+ Coverage   56.05%   56.13%   +0.07%     
==========================================
  Files         306      306              
  Lines       20981    20970      -11     
==========================================
+ Hits        11761    11771      +10     
+ Misses       8371     8346      -25     
- Partials      849      853       +4

[thaJeztah]

Giving this a quick spin;

DOCKER_HIDE_LEGACY_COMMANDS=1 docker --config=.docker-plugin-test --help

Usage:	docker [OPTIONS] COMMAND

A self-sufficient runtime for containers

Options:
      --config string      Location of client config files (default "/root/.docker")
  -c, --context string     Name of the context to use to connect to the daemon (overrides DOCKER_HOST env var and default context set with "docker context use")
  -D, --debug              Enable debug mode
  -H, --host list          Daemon socket(s) to connect to
  -l, --log-level string   Set the logging level ("debug"|"info"|"warn"|"error"|"fatal") (default "info")
      --tls                Use TLS; implied by --tlsverify
      --tlscacert string   Trust certs signed only by this CA (default "/root/.docker/ca.pem")
      --tlscert string     Path to TLS certificate file (default "/root/.docker/cert.pem")
      --tlskey string      Path to TLS key file (default "/root/.docker/key.pem")
      --tlsverify          Use TLS and verify the remote
  -v, --version            Print version information and quit

Management Commands:
  builder     Manage builds
  checkpoint  Manage checkpoints
  config      Manage Docker configs
  container   Manage containers
  context     Manage contexts
  engine      Manage the docker engine
  image       Manage images
  network     Manage networks
  node        Manage Swarm nodes
  plugin      Manage plugins
  secret      Manage Docker secrets
  service     Manage services
  stack       Manage Docker stacks
  swarm       Manage Swarm
  system      Manage Docker
  trust       Manage trust on Docker images
  volume      Manage volumes

Commands:
  build       Build an image from a Dockerfile
  helloworld* A basic Hello World plugin for tests (Docker Inc., testing)
  login       Log in to a Docker registry
  logout      Log out from a Docker registry
  run         Run a command in a new container
  search      Search the Docker Hub for images
  version     Show the Docker version information

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

The new presentation of the plugin looks good to me 🤗

[thaJeztah]

I just realise that I may not have mentioned that on the other PR (and probably something to address separately);

Plugins (most likely) will have subcommands; if so, we should show plugins under Management Command (Alternatively Plugin Commands)

[ijc]

I had one small question, but overall looks good, thanks for picking this up!

[ijc]

Plugins (most likely) will have subcommands; if so, we should show plugins under Management Command (Alternatively Plugin Commands)

Ack, I think that's separate from this change though, #1661 has a separate entry for it:

plugins shuld be able to indicate if they are "management" vs not commands in their metadata and be listed accordingly in e.g. docker help.

[thaJeztah]

Ack, I think that's separate from this change though, #1661 has a separate entry for it:

Ah, yes. I started looking why it wouldn't see .HasSubCommands() but the plugin "proxy" commands don't know if a plugin command has subcommands (yet)

[ijc]

@ulyssessouza I think a Unit terst for decoratedCommandName would increase the score here. Don't know if it would hit the 50% target but nothing else looks to be sanely unit testable to me.

[thaJeztah]

LGTM

left one nit

[silvin-lubecki]

LGTM