[Feature] Allow moving keyboard between top and bottom of the screen

[brendenhoffman]

In desktop mode, the keyboard location is dictated by the location of the cursor. I have always had the keyboard open on the bottom in gaming mod for me so fare, but it also would be useful to be able to move the keyboard in gaming mode as well, an option to choose top or bottom per game would also be helpful. Currently, once the keyboard is open I have not found a way to move it to the other side of the screen.

Current SteamOS version 3.3 beta

Steps for reproducing this issue:

1. Open desktop mode
2. Position cursor on top half of screen, open keyboard, it opens on bottom
3. Position cursor on bottom half of screen, open keyboard, it opens on top