feat(chart): Support dynamic registries with pull secret and pull policy

[Joseph94m]

Closes #20 #21 #22

Edit: also added commit to support deploying a redis. Partially Closing #24 but should be good enough for now.

[Joseph94m]

@djeanprost should be retro-compatible with the existing chart so that current users don't have to make any config changes.

Should support:

• Overriding registry
• Specifying a pullsecret
• Changing the pull policy

[djeanprost]

Looks ok to me except that it fixes #20 , #21 and #22
#23 is another topic.
What a fast MR 🏃

[Joseph94m]

@djeanprost should be good. I was able to test it locally (with a few tweaks to make the redirect work on my local kind cluster).

So it should even accept overriding the registry, and specifying a pull secret.
Can you test the whole feature out and let me know?

# Redis
redis:
  # -- Set to true to deploy a Redis instance as part of this chart (via bitnami/redis sub-chart).
  # When false (default), Redis is treated as an external dependency and you must provide connection details below.
  deploy: true

  # -- Redis architecture when deployed by this chart. Options: "standalone" or "replication".
  # Keep Standalone for now because we do not support replication yet.
  architecture: standalone

  # Image configuration (only used when deploy is true).
  # Override these to pull from a private registry or mirror.
  # When using a non-bitnami registry, you must also set global.security.allowInsecureImages to true.
  # image:
  #   registry: my-private-registry.example.com
  #   repository: bitnami/redis
  #   tag: "8.6.2"
  #   pullPolicy: IfNotPresent
  #   pullSecrets:
  #     - my-registry-secret

  # Persistence for deployed Redis (only used when deploy is true).
  # Disabled by default — Redis is used as a cache/queue, data loss on restart is acceptable.
  master:
    persistence:
      enabled: false