jay_tray_v1 support

[DemiMarie]

• Description:
  StatusNotifierItem and D-bus menus are a replacement for many uses of tray icons. However, there are applications that provide rich user interfaces, such as volume sliders, in the icon menu. These cannot be supported by com.canonical.dbusmenu as it is not expressive enough.

  Jay provides jay_tray_v1 to allow arbitrary icon popups. This allows StatusNotifierItem and dbusmenu to be implemented by third-party components. Since Sway does not implement the tray itself, a companion protocol (discussed at jay-tray-v1: provide a companion protocol for out-of-process panels mahkoh/jay-protocols#2) would be needed so that swaybar or waybar could implement this.

  CC @Alexays for Waybar.