Allow service data to be passed to shell_command

[dale3h]

Description:
Remove the shell command schema so that service data can successfully be passed to the shell command.
Parse args with shlex instead, allowing spaces to be used in the variable data that is passed.

Related issue (if applicable): fixes #2268

Pull request in home-assistant.io with documentation (if applicable): home-assistant/home-assistant.io#

Example entry for configuration.yaml (if applicable):

shell_command:
  garage_opened: './garage_opened.sh --device="{{ device }}" --door={{ door }}'


automation:
  alias: Garage Door is Open
  trigger:
    platform: state
    entity_id: sensor.garage_door
    state: 'open'
  action:
    service: shell_command.garage_opened
    data:
      device: Garage Door
      door: 1

Checklist:

If user exposed functionality or configuration variables are added/changed:

• Documentation added/updated in home-assistant.io

If the code does not interact with devices:

• Local tests with tox run successfully. Your PR cannot be merged unless tests pass
• Tests have been added to verify that the new code works.

[balloob]

That's better ;-)