[Feature Request] Add a global menu

[ryzendew]

Add a global menu in the panel as an applet

[ryanabx]

This should probably be in https://github.com/pop-os/cosmic-applets instead

[leb-kuchen]

@ryzendew The beauty of the applet system is that you can craft your own global menu. I am considering making a application and a places applet based on the gnome counterparts. If you have designs or other applet ideas, feel free to send them to me.