Ability to download multiple packages in a single command

[mdanish-kh]

Description of the new feature / enhancement

The install and upgrade commands support passing in multiple package queries (#219). The download command should also support multiple queries as:

winget download [[-q] <query1> <query2>...] [<options>]

Proposed technical implementation details

No response

[mdanish-kh]

Not sure if this needs to go under #2953 (since the spec PR is still open)

[denelon]

We will look at this separately. We're doing some integration work to support downloading packages from the "msstore" source, so that likely needs to be completed before we can look at feasibility of doing this feature.