x11/swaync: add new port

swaync is a simple notification daemon with a GUI
built for Sway (potentially any WM with wlroots).

Features:
- A panel to view previous notifications
- Show album art for notifications like Spotify
- Do not disturb
- Click notification to execute default action
- Show alternative notification actions
- The same features as any other basic notification daemon

Planned Features:
- Customization through a CSS file
- Slick animations

https://github.com/ErikReider/SwayNotificationCenter