Reassign hardware Next/Prev Buttons

Checklist

[X] I made sure that there are no existing issues - open or closed - which I could contribute my information to.
[X] I'm aware that this is a request for NewPipe itself and that requests for adding a new service need to be made at NewPipeExtractor.
[X] I have taken the time to fill in all the required details. I understand that the feature request will be dismissed otherwise.
[X] This issue contains only one feature request.
[X] I have read and understood the contribution guidelines.

Feature description

AntennaPod has an incredibly neat feature that allows reassigning the NEXT and PREV hardware buttons to different functions.

Specifically there are two separate settings, one for NEXT and one for PREV, each button can be assigned to any of four functions:

PREV (Restart Episode / Video)
NEXT (Skip Episode / Next Video)
FFWD (Fast Forward)
REW (Rewind)

This allows for:

Replacing the default NEXT / PREV function set with FFWD / REW.
Swapping the controls, so PREV can become NEXT and viceversa.
Replacing AND swapping, so NEXT => REW and PREV => FFWD

The rationale for cases 2 and 3 is that, depending on the specifics of the control scheme, one gesture or multi-tap might be easier / faster, and the user will want to assign their most oft-used function to the more accessible control.

For instance, one device might use double tap on right for NEXT, and triple tap on right for PREV. But you use REW more than FFWD, so you will want to map the double tap to REW.

Why do you want this feature?

Almost all True Wireless headsets only have gestures or multi-taps for NEXT and PREV, not REW / FFWD. This seems to be very common in general with Bluetooth headphones and headsets that have hardware buttons, too.

On YouTube there is a lot of podcast-like content that isn't available in true podcast format elsewhere.

When NewPipe's Background Mode is used on this content, the app is effectively turned into a podcast player, a usage scenario where having REW / FFWD is more useful than PREV / NEXT, as podcast listeners will more often have to rewind to accommodate interruptions or distractions, and fast forward over less interesting parts; OTOH, the podcast episode the user will listen to, is often picked from a list at the beginning of the user flow, and then the episode runs for 20 to 60 (or more) minutes, so PREV and NEXT don't see as much use as when listening to a music album or playlist.

Remapping the buttons would allow the user to fast forward or rewind without accessing the device, which is great for a number of scenarios in which fetching and operating it would be cumbersome, a significant waste of time and/or unsafe.

In the background/podcast use case, PREV can also be a major grief, as an inadvertent press restarts the video, thus forcing the user to pick up the device and go on a hunt for the right spot.

PREV can be pressed incorrectly e.g. on a headset that maps "hold PREV" to Volume down, or if an attempt at a triple tap gets misread as a double tap.

Additional information

No response

TeamNewPipe / NewPipe