Raspberry PI garage door controller

[kellerza]

Description:
HomeAssistant only based Garage door controller for Raspberry Pi as an alternative for this controller.

Preferred above integrating this PR #2187

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

Example entry for configuration.yaml (if applicable):

garage_door:
  platform: rpi_gpio

Checklist:

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

• Documentation added/updated in home-assistant.io

If code communicates with devices:

• Local tests with tox run successfully. Your PR cannot be merged unless tests pass
• New dependencies have been added to the REQUIREMENTS variable (example).
• [N/A - internal] New dependencies are only imported inside functions that use them (example).
• [N/A - internal] New dependencies have been added to requirements_all.txt by running script/gen_requirements_all.py.
• New files were added to .coveragerc.

[balloob]

Looks good! 🐬