Reuse input_config_bind_map.
Display current keybind in RGUI.
Allow multi-line messages in RGUI.
Remove an arbitrary hardcoded pad.

Input config RGUI should avoid having to rely too much on autoconfigs.
Keep Xinput pad autoconfig however, as its convenience is worth quite a lot.
Redirect keyboard events to RGUI.

Fixes issue where libretro cores receive keyboard events even though
they are not running (inside RGUI).
Remove obsolete rgui_controller_lut.
Add a FIXME.