feat(swift): Add support for swift object storage

[kmala]

Summary of Changes

Add support to support swift storage

Issue(s) that this PR Closes

refer https://github.com/deis/workflow/issues/306

Associated End To End Test PR(s)

Associated Documentation PR(s)

Ref https://github.com/deis/workflow/issues/306

Associated Design Document(s)

Testing Instructions

Please provide a detailed list for how to test the changes in this PR.

1. Create a Deis Cluster
2. Register an app using swift as storage
3. The app should work fine.

   Pull Request Hygiene TODOs

Please make sure the below checklist is complete.

• [x] Your pull request is concise and to the point (make another PR for refactoring nearby code)
• [x] Your commits follow the commit style guidelines

[deis-bot]

@slack, @arschles and @smothiki are potential reviewers of this pull request based on my analysis of git blame information. Thanks @kmala!

[arschles]

LGTM1, although I don't have a swift cluster handy to test 😉

[kmala]

@arschles you can run single node swift cluster as docker container https://github.com/ccollicutt/docker-swift-onlyone