RetroDock player integration

The original integration files assets/js/player.js,
assets/emulators/adapters.js, assets/emulators/audio-worklet.js and
assets/emulators/player.css are distributed under the GNU General Public
License, version 3 or (at your option) any later version.

You may redistribute and modify these integration files under those terms.
They are provided without warranty; see the complete GNU GPL version 3
in assets/emulators/jsspeccy3/COPYING.txt.

Bundled third-party engines, libraries and system ROMs retain their own
licences and copyright notices. See THIRD_PARTY.md. An emulator licence
does not grant a licence to distribute game ROMs.
