modify the task to give weekly numbers.

ToDo: work job details
Merge branch 'master' of https://github.com/NuGet/NuGet.Services.Dashboard into danliu/gallerystatusreport
add one more block for unique package uploads and remove feed.package.list from availability calculation
Merge pull request #169 from NuGet/danliu/gallerystatusreport

modify the task to give weekly numbers.