Create report analyzing image size trends

[lbussell]

With #745, image sizes are now ingested into our Kusto database. We should create a PowerBI report to analyze trends in image sizes.

I have created some basic documentation on using Kusto queries to analyze image sizes in our internal wiki. It includes a very simple example query to get the size of all images in a repo: https://dev.azure.com/dnceng/internal/_wiki/wikis/Acquisition%20and%20Deployment%20Team/1343/Image-Sizes

[lbussell]

Azure Data Explorer also has the ability to create reports. It seems much easier to use and setup than PowerBI. It is all web-based and you can edit the queries at the same time you edit the visualization. Still supports drill-through and cross-filtering. I set up a simple report that displays a table using one of the example queries I made earlier: https://dataexplorer.azure.com/dashboards/1959953c-8e25-407c-acc1-6b21e411d89c?p-_startTime=1hours&p-_endTime=now#d7e4c06b-74a1-4726-bf37-b4857928da36