Allow users to use VSCode keybinding for remapping

[rebornix]

Ref #1543

    {
        "key": "F3",
        "command": "vim.remap",
        "when": "editorTextFocus",
        "args": {
            "value": ["a", "b", "c", "<Esc>"]
        }
    }

Fixes #1505, #1452

[xconverge]

This is truly awesome, can you remove the Ctrl+n binding now from package.json

[rebornix]

@xconverge I'm afraid we can't, if we remove that, users might first find it broken and then file issues. Let's keep them first and try to deprecate them when we are going to have major release.