Include ARP for uncorrelated apps in `winget export`

Relevant area(s)

WinGet CLI

Description of the new feature / enhancement

When using winget export -o <path>, any apps that cannot be correlated to a package from an available source are not exported to the JSON file. There exists a case where the app currently does not exist in any source, but, could be added to a source between the time of the export and the time of an import. It would be helpful if the app could be correlated at the time of import and imported, rather than being omitted entirely.

Proposed technical implementation details

Have an option or setting to include un-correlated apps in the export. Enabling this would place the ARP data for the applications into a new section within the resulting JSON file from winget export. Enhance winget import to check for this new section, if it is present, attempt correlation using the ARP data there - if a match is returned, install it.

Start by tracing the WinGet CLI paths for winget export and winget import, focusing on how uncorrelated applications and ARP data are handled. Clarify the option or setting and the proposed JSON section before changing anything. Done means export can preserve the ARP data and import can use it for correlation when a package becomes available.