[Spike] Add Helm template support for Splunk Universal Forwarder

[tasen5]

Background

The splunk-operator Helm chart currently supports deploying Splunk Enterprise components
(Standalone, IndexerCluster, etc.) but has no built-in template for a Universal Forwarder (UF).
Teams that need to deploy a UF alongside their Splunk stack must manage it manually or with
separate tooling.

Problem

There is no universalforwarder Helm template in helm-chart/splunk-enterprise/templates/,
making it harder to manage UF deployments consistently alongside operator-managed resources.

Spike Goal

Explore and validate the design of a Helm template for deploying a Universal Forwarder,
specifically answering:

• What Kubernetes resources are needed (Deployment, Secret, ConfigMap)?
• How should the UF be configured (env vars, mounted config file)?
• Should this use the existing CRD pattern or be a standalone Deployment?
• What security context constraints are required?

Spike Output / Definition of Done

• A working prototype template that renders and deploys successfully
• A list of open questions or follow-up tasks for productionizing the template
• Decision on whether to proceed with full implementation

[tasen5]

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