Track additional download information

[kineticsquid]

We're considering additional promotional activities for open-vsx.org, including Credly badges. To do so, we'll need more detailed information about extensions downloads. Currently there is an admin report available, api/admin/reports that provides monthly download totals for the top 15 extensions. Ideally, we'd like to see monthly download numbers tracked for all extensions. (I can see eventually surfacing this for info for extension publishers). Alternately and more tactically, we cold solve our immediate need by increasing the number of extensions in this admin report to say 100 or 200.

[amvanbaren]

@kineticsquid You want to create an achievement system based on extension downloads?

[amvanbaren]

related: https://github.com/eclipse/openvsx/issues/996

[kineticsquid]

@amvanbaren Yes