Update README with all commands

[bexelbie]

amongst others the --script-readable is missing from vagrant service-manager env docker

box and status are missing.

@Preeticp please review the help for this.

bexelbie@bexelbie:~/Vagrant/adb-1.8rc$ vagrant service-manager -h
Usage: vagrant service-manager <command> [options]

Commands:
     env          displays connection information for services in the box
     box          displays version and release information for the box
     restart      restarts the given systemd service in the box
     status       list services and their running state

Options:
     -h, --help   print this help

For help on any individual command run `vagrant service-manager COMMAND -h`
bexelbie@bexelbie:~/Vagrant/adb-1.8rc$ vagrant service-manager box -h
Usage: vagrant service-manager box <sub-command> [options]

Sub-Command:
      version    display version and release information about the running VM
      ip         display routable IP address of the running VM

Options:
      --script-readable  display information in a script readable format
      -h, --help         print this help
bexelbie@bexelbie:~/Vagrant/adb-1.8rc$ vagrant service-manager status -
- - stopped
bexelbie@bexelbie:~/Vagrant/adb-1.8rc$ vagrant service-manager status -h
Usage: vagrant service-manager status [service] [options]

Options:
      -h, --help         print this help

If a service is provided, only that service is reported.
If no service is provided only supported orchestrators are reported.

Examples:
      vagrant service-manager box version
      vagrant service-manager box ip
      vagrant service-manager box version --script-readable
bexelbie@bexelbie:~/Vagrant/adb-1.8rc$ vagrant service-manager restart -h
Restarts the service

Usage: vagrant service-manager restart <object> [options]

Object:
    Object is a service provided via sccli or systemd. For example:
     docker, k8s, or openshift etc.

Options:
      -h, --help         print this help

Examples:
  vagrant service-manager restart docker