Add an iSCSI volume driver for Pure Storage FlashArray

The purpose of this blueprint is to add a Cinder volume driver for Pure Storage FlashArray. It will support the iSCSI protocol and will include at least the minimum set of features required by the Juno release. We will also set up automated CI testing on an OpenStack cluster maintained by Pure Storage in accordance with the third party CI requirement policy.

Pure Storage Technology:
Pure Storage builds all-flash storage arrays. The active/active controller architecture is based on the Purity Operating Environment and providing an adaptive metadata fabric that is scalable, granular to 512B, and protected. Pure systems are based on durable, resilient MLC flash and providing consistent high performance. Pure Storage FlashArrays leverage deduplication and compression technologies to reduce data written thereby lowering costs and increasing density. FlashArrays are designed for non-disruptive operations and can be upgraded or expanded without disruption or performance degradation.