midea: New power_toggle action. Auto-use remote transmitter.

[dudanov]

What does this implement/fix?

1. Adds a new action midea_ac.power_toggle that is useful for reacting to a button click.
2. Now the component automatically detects and uses remote_transmitter component. Useful when using packages. By adding a package configuring remote_transmitter the midea component will automatically start using the extended functionality via IR control.

Types of changes

• Bugfix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Other

Related issue or feature (if applicable): fixes

Pull request in esphome-docs with documentation (if applicable): esphome/esphome-docs#2094

Test Environment

• ESP32
• ESP32 IDF
• ESP8266

Example entry for config.yaml:

# Example config.yaml
button:
  - platform: template
    name: Midea Power Toggle
    on_press:
      midea_ac.power_toggle:

Checklist:

• The code change is tested and works locally.
• Tests have been added to verify that the new code works (under tests/ folder).

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

• Documentation added/updated in esphome-docs.