change dockerfile to multistep build

Dockerfile

@@ -1,21 +1,12 @@
-FROM quay.io/wildfly/wildfly:latest-jdk21
-
-ADD gamertrack-war/target/gepardec-gamertrack.war /opt/jboss/wildfly/standalone/deployments/
-
-COPY ChangeDataSource.sh /opt/jboss/wildfly/ChangeDataSource.sh
+FROM quay.io/wildfly/wildfly:latest-jdk21 AS build
 
-USER root
+WORKDIR /opt/jboss/wildfly/bin
 
-RUN chmod +x /opt/jboss/wildfly/ChangeDataSource.sh
-RUN chmod -R 777 /opt/jboss/
+RUN ./jboss-cli.sh --commands="embed-server --std-out=echo --server-config=standalone.xml, /subsystem=datasources/data-source=ExampleDS:write-attribute(name=connection-url, value=\"jdbc:h2:file:/opt/jboss/wildfly/gamertrackDB;DB_CLOSE_DELAY=-1;DB_CLOSE_ON_EXIT=FALSE;MODE=\${wildfly.h2.compatibility.mode:REGULAR}\")"
 
-USER jboss
-
-RUN /opt/jboss/wildfly/ChangeDataSource.sh
-
-USER root
-RUN chmod -R 777 /opt/jboss/wildfly
-USER jboss
+FROM quay.io/wildfly/wildfly:latest-jdk21
+COPY --from=build /opt/jboss/wildfly/standalone/configuration/standalone.xml /opt/jboss/wildfly/standalone/configuration/standalone.xml
+ADD gamertrack-war/target/gepardec-gamertrack.war /opt/jboss/wildfly/standalone/deployments/
 
 
 ENTRYPOINT ["/bin/bash", "-c", "/opt/jboss/wildfly/bin/standalone.sh -b 0.0.0.0"]