amc monitor is not documented

[Alexis Janon]

The amc CLI has a monitor subcommand which prints AMS events (similarly to the 1.0/events AMS HTTP API endpoint).
However, that subcommand is undocumented in the amc help text:

$ amc --help
Available Commands:
  addon Manage addons
  application Manage applications
  benchmark Benchmark your Anbox Cloud deployment
  completion Generate the autocompletion script for the specified shell
  config Manage AMS configuration
  delete Delete an instance
  exec Execute a command inside an instance
  help Help about any command
  image Manage images
  info Provide general information about the connected AMS service
  init Create an instance but do not start it immediately
  launch Launch an instance
  list List instances
  logs Show runtime logs of an instance
  node Manage nodes
  remote Interact with remote AMS daemons
  shell Open a shell inside a running instance
  show Show information about an instance
  show-log Show an instance log file
  start Start an existing instance
  stop Stop a running instance
  wait Wait for an instance to reach a specific condition

It is also not documented in the Anbox cloud docs:
https://documentation.ubuntu.com/anbox-cloud/en/latest/reference/cmd-ref/amc-command-reference/landing/

Running the subcommand with --help shows a small help text, which could also be extended:
$ amc monitor --help
Monitor AMS events

Usage:
  ams.amc monitor [flags]

Flags:
      --format string Output format - 'json' or 'yaml' (default "yaml")
  -h, --help help for monitor
  -t, --type string Comma-separated filters for events types - 'lifecycle', 'logging', 'operations' or 'all' (default "all")