Refactor data-node download and assembly (#14963)

* Refactor data-node download and assembly

- Download OpenSearch aarch64 distribution in addition to x64
- Extract OpenSearch distribution into "target/opensearch/*" instead of
  "bin/download".
- Include OpenSearch distributions in "dist/" instead of "bin/" in
  assembly

* Fix data-node test container creation

* Adjust OpenSearch location for architecture dependent locations

* If the configured location exists, use it

Otherwise, check for architecture dependent distribution directories.

* Switch default config file to locations that work with the tarball

* Rename datanode.jar to graylog-datanode.jar

* Rename datanodectl to graylog-datanode.sh

* Include graylog-datanode.sh in assembly as bin/graylog-datanode

* Add a jvm.options config file

* Add a production log4j2.xml config file

* Use bundled JVM if it exists

* fixed docker image for datanode integration tests

---------

Co-authored-by: Tomas Dvorak <tomas.dvorak@graylog.com>

data-node/src/main/java/org/graylog/datanode/Configuration.java

@@ -49,6 +49,8 @@ import java.util.Collections;
 import java.util.List;
 import java.util.Optional;
 
+import static org.graylog2.shared.utilities.StringUtils.f;
+
 /**
  * Helper class to hold configuration of Graylog
  */
@@ -156,7 +158,19 @@ public class Configuration extends BaseConfiguration {
     }
 
     public String getOpensearchLocation() {
-        return opensearchLocation;
+        // If the configured location exists, just use it.
+        if (Files.exists(Path.of(opensearchLocation))) {
+            return opensearchLocation;
+        }
+
+        // Otherwise check if the architecture dependent distribution exists.
+        final var osArch = System.getProperty("os.arch");
+        return switch (osArch) {
+            case "amd64" -> f("%s-linux-x64", opensearchLocation);
+            case "aarch64" -> f("%s-linux-aarch64", opensearchLocation);
+            default ->
+                    throw new UnsupportedOperationException("Unsupported OpenSearch distribution architecture: " + osArch);
+        };
     }
 
     public String getOpensearchVersion() {