Description of the new feature/enhancement

It would be great to be able to set image files (like icon or backgroundImage) in settings.json using data URI scheme. This could be useful when making backups or clones of Windows terminal settings, when syncing them with other devices, etc., especially when our custom profiles are concerned.

Proposed technical implementation details

An example fragment from settings.json for a custom icon:

{
    "guid": "{7895828e-1e14-4068-89b4-582567b7495e}",
    "name": "MySQL",
    "commandline": "wsl.exe mysql -u username -p",
    "hidden": false,
    "icon": "data:image/png;base64,iVBORw0KG..............goAJRU5ErkJggg=="
}