Add a way to download all stats in data portal metric page

[mburrus]

Describe the feature you'd like Add a 'Download' button to the Metrics tab in data portals. An ESS-DIVE user has given us the feedback that they would like to be able to download a report on their data portal metrics. The exact format of the desired download file was not specified, I imagine there could be need for a tabular report and/or a graphic report (much like the graphics currently displayed for data metrics).

Is your feature request related to a problem? Please describe. When a data portal creator or collaborator visits their Metrics tab in their portal, they have no way to export any statistics other that to take a screenshot or manually note the stats.

Additional context May be related to #1298