Add support for deploymentAnnotations

[nanderson94]

Allow user to optionally configure annotations on the worker and web Deployments via Chart values. This could be used (for my example) with integrations for ImageStreams in OKD/OpenShift.

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Why do we need this PR?

While Annotations generally have a wide variety of uses, I found the need for this feature while working with OKD/OpenShift's ImageStreams. ImageStreams will modify Deployments according to a user's configuration (via Deployment Annotations) to use specific digests or even the built-in registry.

Changes proposed in this pull request

• Allow users to specify Annotations to the Web/Worker Deployments via the new deploymentAnnotations field under web and worker respectively.

Contributor Checklist

• [X] Variables are documented in the README.md
• [X] Which branch are you merging into?
  • master is for changes related to the current release of the concourse/concourse:latest image and should be good to publish immediately
  • dev is for changes related to the next release of Concourse (aka unpublished code on master in concourse/concourse)

Reviewer Checklist

This section is intended for the core maintainers only, to track review progress. Please do not fill out this section.

• [ ] Code reviewed
• [ ] Topgun tests run
• [ ] Back-port if needed
• [ ] Is the correct branch targeted? (master or dev)