Add a menu to Linux

The app works on Linux, but the right click on top of the icon does not display the list of menus. This is a [known Electron limitation](https://electronjs.org/docs/api/tray#traypopupcontextmenumenu-position-macos-windows).

I can see this being fixed in one of 2 ways:
1. Add a _UX/UI_ label and think of this problem as a current bad design and iterate from there
2. Figure out a way to show the menu

The menu I am talking about is this one:

P.S.: This is particularly important because it is on this menu that the _quit_ action is shown. Currently, Linux users do not have an easy task quitting Palbum.