decklink: Add new persistent-id property and sort devices by persistent ID

decklink: Add new persistent-id property and sort devices by persistent ID

The order of the devices iterator from the SDK is undefined and can
randomly change.

Keep the device-number property for backwards compatibility and
simplicity but prefer the persistent-id property and also use it for the
device provider implementation.

Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/3078>