feat(otel-ext): add Generic OTel Collector service binding support with mTLS from credentials

[dimitarKiryakov]

Summary

• Introduces a Generic OTel Collector path in the OpenTelemetry agent extension: set sap.otel.collector.cf.binding.name to the name of any CF service instance (managed or user-provided) and the extension auto-configures the otlp exporter to send data there.
• mTLS client credentials (tls.crt, tls.key) and an optional server CA (tls.ca.crt) are read directly from the service binding credentials — no external certificate service required.
• Bearer token fallback: if no mTLS credentials are present, the optional token field is sent as Authorization: Bearer <token>.
• Zero breaking changes: existing CaaS and Cloud Logging users require no changes; the new supplier is a no-op unless the new property is set.

Changes

Module	What changed
ExtensionConfigurations	New OTEL_COLLECTOR.BINDING_NAME config property
CloudFoundryServicesAdapter	New findByName(String) method to locate a binding by instance name across all service labels
OtelCollectorServiceProvider	Reads the binding name from config, delegates to CloudFoundryServicesAdapter.findByName()
OtelCollectorBindingPropertiesSupplier	Resolves endpoint URL, writes PEM files for mTLS/CA, sets OTel exporter properties
CloudLoggingConfigurationCustomizerProvider	Wires OtelCollectorBindingPropertiesSupplier as first entry in the supplier chain
README.md	Documents the new feature; removes stale BTP Certificate Service sections

Test plan

• Verify 241 existing module tests still pass: mvn test -pl cf-java-logging-support-opentelemetry-agent-extension
• Verify shaded jar builds: mvn package -pl cf-java-logging-support-opentelemetry-agent-extension -DskipTests
• Manual smoke test: bind a user-provided service with url, tls.crt, tls.key; confirm mTLS exporter properties are set at startup
• Manual smoke test: bind a user-provided service with url and token only; confirm bearer header is set
• Confirm that an app with only a Cloud Logging or CaaS binding and no sap.otel.collector.cf.binding.name property behaves identically to before

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