Add start of the EC2/S3 API testing to tempest

Continues the effort of the https://review.openstack.org/#/c/3064/

* add EC2 keypair and volume tests
* add EC2 snapshot from volume test
* add EC2 floating ip disasscioation
* add EC2 operation on security group
* add EC2/S3 image registration
* add EC2 instance run test
* add Integration test with ssh, console, volume
* add S3 object and bucket tests

Change-Id: I0dff9b05f215b56456272f22aa1c014cd53b4f4b
25 files changed