Add proper window hints so that i3 doesn't try to tile popups

[KP2048]

Discussed in #133

^{Originally posted by Witherking25 September 30, 2023}
not sure how fixable this is, but whenever a program running under cassowary opens a popup, my window manager, i3, says "ooh, new window, must tile!" and resizes all the windows and tiles it. this is mainly due to the window hints not being set on the rdp window becasue it is normally not a popup window, so it shouldn't float. but for popup windows, it obviously should float lol.

[KP2048]

in case you are wondering, you can in fact add window atoms to existing windows you don't own, as long as you can get a window handle. setting _NET_WM_WINDOW_TYPE_DIALOG on any windows that are deemed popups should be sufficient for most tiling window managers