Oracle Linux base images

Initial commit of Oracle Linux 6.5, 6.6 and 7.0 to the Docker official library.

Signed-off-by: Avi Miller <avi.miller@oracle.com>
We need both ```6.latest``` and ```7.latest```, at least for a while: there are a bunch of Oracle products that haven't been certified on OL7 yet, so we need customers to be able to pull the latest release of OL6.

I'm happy to add ```latest``` to OL7 as well.