opentelemetry tracer: add Dynatrace resource detector (#30824)

* Add Dynatrace resource detector

Co-authored-by: Thomas Ebner <96168670+samohte@users.noreply.github.com>
Signed-off-by: Joao Grassi <joao.grassi@dynatrace.com>

* PR suggestions

Signed-off-by: Joao Grassi <joao.grassi@dynatrace.com>

* Add tests for Dynatrace file reader

Signed-off-by: Joao Grassi <joao.grassi@dynatrace.com>

* PR suggestions

Signed-off-by: Joao Grassi <joao.grassi@dynatrace.com>

* schemaUrl_ -> schema_url_

Signed-off-by: Joao Grassi <joao.grassi@dynatrace.com>

* PR suggestions and changelog

Signed-off-by: Joao Grassi <joao.grassi@dynatrace.com>

---------

Signed-off-by: Joao Grassi <joao.grassi@dynatrace.com>
Co-authored-by: Thomas Ebner <96168670+samohte@users.noreply.github.com>

Mirrored from https://github.com/envoyproxy/envoy @ be410d6121fefb2d57468261180aa354fb8020b5

envoy/extensions/tracers/opentelemetry/resource_detectors/v3/dynatrace_resource_detector.proto

@@ -0,0 +1,25 @@
+syntax = "proto3";
+
+package envoy.extensions.tracers.opentelemetry.resource_detectors.v3;
+
+import "udpa/annotations/status.proto";
+
+option java_package = "io.envoyproxy.envoy.extensions.tracers.opentelemetry.resource_detectors.v3";
+option java_outer_classname = "DynatraceResourceDetectorProto";
+option java_multiple_files = true;
+option go_package = "github.com/envoyproxy/go-control-plane/envoy/extensions/tracers/opentelemetry/resource_detectors/v3;resource_detectorsv3";
+option (udpa.annotations.file_status).package_version_status = ACTIVE;
+
+// [#protodoc-title: Dynatrace Resource Detector config]
+
+// Configuration for the Dynatrace Resource Detector extension.
+// The resource detector reads from the Dynatrace enrichment files
+// and adds host/process related attributes to the OpenTelemetry resource.
+//
+// See:
+//
+// `Enrich ingested data with Dynatrace-specific dimensions <https://docs.dynatrace.com/docs/shortlink/enrichment-files>`_
+//
+// [#extension: envoy.tracers.opentelemetry.resource_detectors.dynatrace]
+message DynatraceResourceDetectorConfig {
+}