Shared configmap and secrets between workers and pachd (potentially breaking change)

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Right now, config values are passed directly to pachd via env vars (ie STORAGE_BACKEND) some of these values are also mirrored in worker_rc.go in pachyderm. Further, some values are passed through Pachd to the workers (ie. WORKER_IMAGE)

Instead, we should have global configuration configmaps/secrets, which get read into pachd and the workers dynamically via envFrom This would eliminate the need to for PACHD to have env vars which only pass data to the workers

Questions:

• Should we have two config maps (one for pachd and one for workers) or is it ok for workers to get all pachd config?)

Considerations:

• Upgrading Pach Versions (ie. if configmap values change, but old pachd/workers still around)
• Versioned configmap names? (to ensure correct data read)

For now I think we can move storage secrets over without too much trouble, but further thought is required for the configuration data

AB#150

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Shared secrets now exists for storage layer