Enable bosh director to assign prefix addresses

[fmoehler]

At the moment the bosh director is only enabled to assign single ip addresses. However in some use cases (please refer https://github.com/cloudfoundry/community/blob/main/toc/rfc/rfc-0038-ipv6-dual-stack-for-cf.md ) it might be necessary to assign a block of ip addresses (prefixes) to a vm. This gets especially interesting in the ipv6 context as ips are globally routable.

We are currently working on several PRs that enables the director to assign prefixes on aws. For more details on the implementation details please check out the descriptions in the PRs:

• Director
• aws-cpi
• bosh-agent