[FEATURE REQUEST] Separate key bindings for each of the 3 screenshot modes

[BrodieRobertson]

Currently when you press print screen it opens the GUI for taking a screenshot, this adds in an extra step to every screenshot operation. A lot of desktops get around this by adding bindings for each of the screenshot modes, for example print screen take a full screen screen shot, shift + print screen takes a selection screen shot, etc.