[Feature Request] Toggle/Combo button for enabling and disabling PAL Video Timing Override on the fly

[Ryunam]

Whenever playing PAL PS1 games - which were almost always converted to 50Hz in a very unoptimized state, leading to much slower gameplay - the core option Video -> "PAL (European) Video Timing Override" works wonders for forcing all such titles to run with NTSC speeds.
This option was introduced quite a few years ago, further to a long conversation we had in issue #67

(That first message was posted way back in 2016, 8 years ago! Truly insane how time flies...)

The only drawback to forcing NTSC speeds on all such games, inevitably, is that for certain scenes that have a hard-coded timing it is easy to encounter some desyncs between the video and the audio. This commonly occurs with FMV videos for example and is a natural byproduct of forcing a 50Hz game to run at 60Hz. It happens on real hardware too, when you use Action Replay cheat codes to achieve the same effect.

So I thought, one way of allowing the user to at least work around this issue would be creating a new option that provides a toggle button, or a combination of buttons, that would allow to switch on the fly between enabling and disabling the PAL override, saving the user from the hassle of having to enter the Menu every single time.
This would be similar to the existing combo options for the Analog button: ideally we should have multiple values to accommodate all scenarios where any of the buttons usable for this are actually used already for some in-game function (for example, we could have "L2", "R2", "L2+R2", "L3", "R3", "L3+R3" and so on).

Hopefully this is doable! I did try dabbling in the code myself for this purpose, but I have yet to figure out how to implement this reliably...