Hastlayer-accelerated ImageSharp Orchard Core integration (HAST-192)

[Piedone]

Integrate the Hastlayer-accelerated ImageSharp implementation (https://lombiq.atlassian.net/browse/HAST-170) into Orchard Core.

The point is to be able to demonstrate the performance difference between the default (CPU-using) image resizing and the Hastlayer-accelerated one. Thus, the implementation should take over whenever image resizing happens in OC with ImageSharp. We should be able to showcase the performance difference, like the response time of an HTTP request.

Jira issue