Roadmap: ACR Image Pull Performance - ACR Image Pull Provisioned Throughput Reservation

[johnsonshi]

A lot of customers have been asking for (1) multiple Tbps egress throughput and (2) high API concurrency for an ACR geo-replica. This work item tracks ACR's work on offering an ACR control plane flow where registry admins can configure an "image pull provisioned throughput reservation", a paid reservation which can guarantee a customizable egress throughput and API concurrency (for APIs related to image pull operations).