Support for configuring custom imagePullSecrets

[prashant231299]

Description:
The amazon-cloudwatch-observability Helm chart currently does not allow the configuration of custom imagePullSecrets. This limitation prevents users from pulling container images from private registries, which is a common requirement in enterprise environments.

Expected Behavior:
The Helm chart should provide a configurable imagePullSecrets parameter in values.yamlso that users can specify secrets to pull images from private registries.

Current Behavior:
There is no option in the chart to configure custom imagePullSecrets. As a result, image pulls fail when the registry requires authentication.

Steps to Reproduce:

1. Deploy the a amazon-cloudwatch-observability Helm chart in a cluster where required images are stored in a private registry.
2. Attempt the deployment without the ability to configure imagePullSecrets.
3. Observe the failure to pull images due to authentication errors.

Proposed Solution:

• Add a configurable imagePullSecrets field in values.yaml.
• Update Deployment/DaemonSet manifests to reference the provided secrets.

Additional Context:
Adding support for imagePullSecrets will make the chart usable in more secure and restricted environments.