Bon le widget d'embed commence à ressembler à quelque chose !

Second iteration of #Funkwhale's embed widget today, with:

- Multi tracks mode (as seen on first video)
- Better color palette thanks to @Troll
- Better accessibility (the whole think is now usable from keyboard only)
- Embed wizard inside Funkwhale to generate embed code, with preview (first video)
- Tweaks to have a responsive widget on really small widths
- Tests on my personnal website (second video)
- Other styling tweaks

I'm so happy to have this included in the next release!

@eliotberriot c'est très joli !!

(et la musique de la horde du contrevent, hihi :3 )

@Nausicaa merci, je suis content que ça te plaise :3