Initial commit for the AWS EC2 and VPC API standalone service project

This project serves two purposes:
1. Add AWS VPC API support implementation into OpenStack.
2. Serve as a prototype for future extraction of nova's EC2 API layer
into a separate service.

As agreed with Michael Still (nova PTL) and Joe Gordon we're adding the
VPC API implementation as a separate service and not contributing it as
a nova EC2 patch. Later this separate service is supposed to
accommodate extracted EC2 API as well and be accepted back into
OpenStack as a part of Compute.
Right now for the first version the idea is to create fully functional
standalone EC2 service by:
1. Proxying existing EC2 API calls into existing nova EC2 API layer.
2. Implementing here the VPC API related calls and funcionality
This standalone service when installd will be replacing the endpoint
for EC2 API in keystone and storing nova's EC2 API endpoint internally
in config for proxying existing EC2 API calls.

Change-Id: I1bffb09b6e2f9376ab6d74f2e8f68c93d3ba2c0c
Merge "Initial commit for the AWS EC2 and VPC API standalone service project"