[feature request] Save Hotkeys to Autoconfig Profile

Description

Because hotkeys are a very personal preference, we specifically disallow any hotkeys from being assigned in autoconfig profiles except for the menu toggle on various pads' "home" buttons. However, many people who swap among multiple controllers want to have hotkeys available on their pads without constantly revisiting the hotkey menu to reassign them, since they're stored as static keycodes that may not be consistent across gamepads.

This comes up fairly often on the subreddit and I typically tell users to add the hotkey assignments to their autoconfig profile via a text editor, which works well, AFAIK. However,

I propose adding an option to "save hotkeys to autoconfig profile" (and probably would need a corresponding "reset hotkeys to default", as well) to settings > input > hotkeys so users can achieve this without needing to do it manually via text editor.

Expected behavior

Custom hotkeys that follow controllers around as you swap among them

Actual behavior

hotkeys are tied to the controller on which you set them

Steps to reproduce the bug

1. plug in a pad
2. set some hotkeys
3. plug in another pad
4. try to use those hotkeys

Bisect Results

always. it's normal behavior

Version/Commit

You can find this information under Information/System Information

• RetroArch: 1.16.0

Environment information

• OS: all
• Compiler: any

@sonninnos , pinging you on this as the resident menu guru. Do you know of any technical dealbreakers on something like this?

No files, tests, or code entry points are named. Start with Settings > Input > Hotkeys and the autoconfig profile format; done means users can save custom hotkeys to a profile, reset them to defaults, and have them follow swapped controllers without manual text editing.