Add a controller friendly virtual keyboard

[AJenbo]

Some devices like RG350 do not have a build in virtual keyboard, this prevents them from partake in multiplayer games (as well as a few other features) as they cannot enter the password for the game.
To solve this we should provide a simple virtual keyboard for such platforms, since these devices usually also do not have a touch screen it should be usable via a game controller.

A couple of options:

https://github.com/diasurgical/devilutionX/tree/4c2a43b23e92adcb1d047fdd52e10fb53c9471ff/vita/danzeffSDL

https://github.com/benob/rs97_st-sdl/blob/master/keyboard.c

[glebm]

There is also my implementation in Commander that is compatible with both SDL1 and SDL2 https://github.com/od-contrib/commander/blob/main/keyboard.cpp

[AJenbo]

@glebm do you have a screenshot?

[glebm]

https://github.com/od-contrib/commander/releases/

[john-parton]

Dosbox and Dosbox pure have an onscreen keyboard that works with a pointer. It's slow for inputs, but it works really well.

https://github.com/schellingb/dosbox-pure#on-screen-keyboard