[Feature Request] controller test section

[ndnnox]

Overview

add a controller test feature where it allows you to test and a controller functionality and identify which controller is being used

Smaller details

allows for button testing to make sure if buttons are being pressed, if motion is functioning properly, if rumble is functioning properly, as well as being able to identify which controller is being used. yuzu had a similar feature.

Nature of request

to make life easier

Why would this feature be useful?

this feature would be useful because it would make testing alot easier, we wouldnt have to keep starting up games and load all that shader cache for the sake of testing certain buttons or stick drift or motion.

[ndnnox]

also not sure if this would be a good place to add this other request or not but maybe lock the joystick to 8 different positions for games like super smash bros.

[usr20210909]

This PR seems to go in that direction: #533