Bonjour device discovery

This is only possible in the experimental builds, and is expected to be usable by modules in v3.2

Bonjour is a standardised method of device discovery, utilising MDNS.

Companion allows for easily discovering devices, to help users with configuration.

You can do this by defining a config field such as:

{
	type: 'bonjour-device',
	id: 'bonjour_host',
	label: 'Bonjour Test',
	width: 6,
},

and in your companion/manifest.json:

	"bonjourQueries": {
		"bonjour_host": {
			"type": "blackmagic",
			"protocol": "tcp",
			"txt": {
				"class": "AtemSwitcher"
			}
		}
	}

These two structures are linked by the common id, in the future this will allow us to automate device discovery further.

In the UI, this field will look like:

The 'Manual' option is always shown, and must be handled to allow users to manually specify an address for environments where Bonjour does not work.
This can be achieved with further config fields such as:

{
	type: 'textinput',
	id: 'host',
	label: 'Target IP',
	width: 6,
	isVisible: (options) => !options['bonjour_host'],
	default: '',
	regex: Regex.IP,
},
{
	type: 'static-text',
	id: 'host-filler',
	width: 6,
	label: '',
	isVisible: (options) => !!options['bonjour_host'],
	value: '',
},

Note the presence of the isVisible function, to control the visibility of the fields depending on whether a bonjour discovered device has been selected.
In this example, it is using an empty 'static-text' field, to keep the layout consistent.

In your module code, the bonjour_host will have a value such as 10.0.0.1:8000 or null.

Writing your Bonjour Query

We currently support a subset of the possible query options. In all queries, the type and protocol must be set.
If your device needs further filtering, this can be done by specifying any txt field values the entries must have.