Add initial audit logging pipeline (API, SDK, OTLP exporter, and autoconfigure)

[hilmarf]

Summary

This PR introduces an initial end-to-end audit logging pipeline for OpenTelemetry Java, including new API and SDK modules, OTLP HTTP export support, and autoconfiguration wiring.

What changed

• Added a new Audit API module with core audit types and contracts, including:
  • provider and global provider access
  • logger and logger builder
  • audit record builder and receipt model
  • actor/outcome semantics and delivery exception handling
• Added a new Audit SDK module with runtime implementation, including:
  • SDK audit provider and logger implementations
  • read/write record model
  • exporter and processor contracts
  • processor implementations (simple, batch, multi, noop)
  • in-memory exporter for testing scenarios
• Added a new OTLP HTTP audit exporter module:
  • OTLP audit record data adapter
  • HTTP exporter and builder for audit records
• Added autoconfigure integration for audit:
  • audit provider configuration bootstrap
  • audit exporter selection and SPI loading
  • new SPI interface for configurable audit exporters
• Wired new modules into the build:
  • included new projects in settings
  • added audit SDK to the sdk aggregate module
• Added a GitHub workflow for fork synchronization:
  • sync-fork.yaml

Configuration behavior

• New property: otel.audit.exporter
• Default exporter: otlp
• Special value: none (disables audit exporting)
• Validation: configuration fails if none is combined with other exporters or if an unknown exporter name is configured

Why

This lays the foundation for first-class audit logging support in OpenTelemetry Java with:

• clear API/SDK separation
• pluggable exporter model
• out-of-the-box OTLP export path
• autoconfigure-based runtime setup

Notes

• This change is primarily additive and introduces new modules and integration points.
• No existing tracing/metrics/logging APIs are replaced by this PR.