Add GPU info to product info

[martonsereg]

Number and type of attached GPUs are currently not returned by the product info API.
Discover the options on the different cloud providers and make it available in the product information.

[prekoa]

AWS:
https://docs.aws.amazon.com/AWSEC2/latest/WindowsGuide/elastic-gpus.html#elastic-gpus-basics

Price:
https://aws.amazon.com/ec2/elastic-gpus/pricing/

GPU instances:
https://docs.aws.amazon.com/dlami/latest/devguide/gpu.html

Google:
There are 4 types of GPUs (1-2 beta), and some machine groups don't support the GPU.
https://cloud.google.com/compute/docs/gpus/#introduction

GPU models depend on the number of RAMs, number of CPUs, and zones.
https://cloud.google.com/compute/docs/gpus/#gpus-list

Instances with GPUs have specific restrictions.
https://cloud.google.com/compute/docs/gpus/#restrictions

The API includes prices, but only for 3 types, and not in all zones.

Azure:
Azure does not support attached GPUs.

GPU instances:
https://docs.microsoft.com/en-us/azure/virtual-machines/windows/sizes-gpu