Add information connecting to Juliaup to Windows Store Site

[grhartl]

Currently all links only lead to Julia itself, and juliaup is not mentioned anywhere. This may be confusing, and makes the possibilities of Juliaup hard to recognize. Maybe a link to this repository, a short description that it also contains juliaup as version manager and a few basic commands could be added to the description? Is it sufficient to modify storesubmission/pdps/en-us/PDP.xml ?

[davidanthoff]

I think we should just eventually add setup documentation to the normal Julia documentation, and explain the juliaup story there.

I'm not entirely sure whether editing the file you mentioned would be enough, but we could try. I originally entered the text in the description on the store submission website.