Update OTelSpan.java

Add parsing of db.statement and db.user attributes for OpenTelementy Plugin.

This will allow users to write an own Elastic APM Plugin for a not yet supported database and also add the executed statement to the span (like with the supported DBs)

apm-agent-plugins/apm-opentelemetry/apm-opentelemetry-plugin/src/main/java/co/elastic/apm/agent/opentelemetry/tracing/OTelSpan.java

@@ -169,9 +169,13 @@ private void onSpanEnd(co.elastic.apm.agent.impl.transaction.Span s) {
             type = "db";
             subType = dbSystem;
             String dbName = (String) attributes.get("db.name");
+            String dbStatement = (String) attributes.get("db.statement");
+            String dbUser = (String) attributes.get("db.user");
             s.getContext().getDb()
                 .withType(subType)
-                .withInstance(dbName);
+                .withInstance(dbName)
+                .withStatement(dbStatement)
+                .withUser(dbUser);
             s.getContext().getServiceTarget()
                 .withType(subType)
                 .withName(dbName);