[acapy] Observability: Helm chart integration

[i5okie]

Description

Add native OTel configuration support to the acapy Helm chart, enabling both standalone deployment and sub-chart usage (e.g. inside vc-authn-oidc, traction, endorser-service).

Requirements

• Add a native otel: section to values.yaml for per-chart settings (serviceName defaulting to the release name) and shared settings (enabled, endpoint, protocol, tracesExporter, metricsExporter, logCorrelation)
• Support global.otel.* for all shared settings so that when acapy is deployed as a sub-chart, the parent's global values cascade down automatically; templates should prefer global with a local fallback: {{ .Values.global.otel.endpoint | default .Values.otel.endpoint }}
• Render OTEL env vars conditionally in templates/deployment.yaml when otel.enabled (or global.otel.enabled) is true — treat OTel as a first-class chart feature

Acceptance Criteria

• otel.enabled: true + otel.endpoint in values.yaml results in correct env vars in the deployed pod
• When deployed as a sub-chart, global.otel.* values from the parent chart are respected
• Traces appear in Tempo after deployment
• HTTP metrics appear in Mimir after deployment