Add borderless windowed option

[Keith94]

The hotkeys F7 and F8 don't seem to work correctly or cause the window the glitch out. Please add a proper borderless windowed option in game or in .ini file.

[bigtweekx]

A workaround is to maximize the window using they keyboard shortcut: Win Key + Up arrow, and then press F8 to remove window border.
I recommend doing this in the main menu after logging in.

[pnill]

I'll take a look and see if we can determine why the hot keys are not working properly, and also look into seeing if we can add an option in the menus to support this from launch.