Add sound effects for PPSSPP interface navigation

[hrydgard]

Fixes #13225 .

Adds SELECT, BACK, CONFIRM, TOGGLE_ON and TOGGLE_OFF sound effects to the PPSSPP UI.

If anyone have better sounds, feel free to suggest replacements. Must not be under any license not compatible with PPSSPP's license.

• Add an option
• Replace the wave files
• Find better places to hook up the sound effects to avoid double-triggering back/confirm

Still needs a lot of polish, but sets up the framework.

[hrydgard]

Turned it off by default since it needs more polish for that (and possibly shouldn't be on at all for mouse clicks, etc). But ready to start playing with.

[hrydgard]

Just gonna go ahead and merge this.

Remember, it's off by default so turn it on in System settings (or UIAudio in the .ini file) if you want to try it.