Support for ILB, Disk Cache, VM Image Capture and region VNet

Implemented following:

1. Support for internal load balancer
2. Disk host caching while attaching disk
3. Support for regionwise VNet
4. Support for capturing VM as VM image
5. Bug fix: unable to create affinity group as a part of vnet creation
6. Bug fix: don't re-throw 404 error from get network config