feat: add support for configurable service account for tooljet app

[javidaslan]

Description:

This PR introduces support for customizing the Kubernetes ServiceAccount used by the ToolJet deployment. This enables more secure and flexible integration with cloud-native identity management systems, such as IAM Roles for Service Accounts (IRSA) in AWS EKS.

Key Features:

• serviceAccount.create: Enables or disables automatic creation of a ServiceAccount
• serviceAccount.name: Optionally specify a custom ServiceAccount name
• serviceAccount.annotations: Support for adding annotations (e.g., eks.amazonaws.com/role-arn)

Helm Values Example:

serviceAccount:
  create: true
  name: tooljet-irsa
  annotations:
    eks.amazonaws.com/role-arn: arn:aws:iam::123456789012:role/ToolJetRole

Files Updated:

• values.yaml — adds new service account configuration options
• templates/serviceaccount.yaml — creates the ServiceAccount resource conditionally
• templates/deployment.yaml — injects serviceAccountName into the pod spec
• templates/_helpers.tpl — helper to resolve the final service account name

Backward Compatibility

This change is fully backward compatible. If serviceAccount.create is false and no name is provided, default Kubernetes behavior will apply.