Rename indexes and fks to support Oracle's 30 char restriction

This is the beginning of try #2 at oracle support in the cloud controller.  For more information see the old oracle PRs:

* https://github.com/cloudfoundry/cloud_controller_ng/pull/44
* https://github.com/cloudfoundry/cloud_controller_ng/pull/47
* https://github.com/cloudfoundry/cloud_controller_ng/pull/46
* https://github.com/cloudfoundry/cloud_controller_ng/pull/42
* https://github.com/cloudfoundry/cloud_controller_ng/pull/41
* https://github.com/cloudfoundry/cloud_controller_ng/pull/38

This time my team has loose timelines requirements so I plan to do this one step/PR at a time.

This PR only renames the indexes and fks to a length of < 30 chars.  I've also provided tests that ensure nothing is adding in the future longer than 30 chars so I don't have to continually chase other migration changes.

Once this PR is accepted then I'll move onto another aspect of the integration.