Add F3 shortcut to toggle the dual layout feature

What’s the Problem?

As someone who’s comming from an KDE Background (Dolphin as Filemanager) i’m used to different Keyboardshortcuts. The Problem is that i see no way of that option in Files. Not in an .json like the Terminal setting or an GUI option

Solution/Idea

A way to customize the Keyboard shortcut without modification of the source code. Like through the Settings in the Settings Page or through an .json similar to that of Terminal:

{
    "$schema": "https://aka.ms/terminal-profiles-schema",
    "actions": 
    [
        {
            "command": 
            {
                "action": "splitscreen",
            },
            "keys": "ctrl+alt+s"
        },
    ]
}

with a Syntax like that example.

For these Types of things its nice to have an extended list for all actions like this one again from Terminal https://docs.microsoft.com/en-us/windows/terminal/customize-settings/actions

Alternatives

An Alternative is through the Registry with an key in HKCU\SOFTWARE\Files-community\shortcuts and put the “Actions” into an REG_SZ type and the shortcut in the data field.

Priorities

Capability	Priority
The change of keyboard shortcuts without manual change of the sourcecode	Must
Changing it through an .json, with well documented actions	Should
Changing it through the Settings in the App with entries for each Action	Could

Files Version

v2.0.13.0

Windows Version

Windows 10 Pro Version 20H2 Build 19042.1288

Additional comment

No response

[LastDerivative]

@yaichenbaum I can take this on

[yaira2]

Merging with #1660