Display (and other device) control integration support

[waydabber]

It would be nice to allow control compatible devices with custom communication features. This should include the ability to set and get ranged and bool values and execute commands.

The feature should work both with predefined and custom controls (#2300)

The following integration options should be available:

• cli/shell script
• HTTP/S
• notification dispatch
• URL schema

[waydabber]

This is how integration can be configured:

[waydabber]

An example on how to configure your Yamaha AV to be controlled with BetterDisplay instead of the display's audio (useful for those who want to use an AV receiver for example. With the same style you can of course add any kind of other controls, or control your Smart TV via HTTP/S or by invoking scripts and using many of the readily available CLI based control tools (for LG TVs for example).

Control integration gives the proper working Volume slider for a non-DDC display (TV) if configured to do so. Keyboard control of course works as expected.

Otherwise custom or predefined hardware integration controls appear under "Hardware Control".