Initial log4j support

Backend/xslt-rest/pom.xml

@@ -14,6 +14,7 @@
     <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
     <jackson.version>2.14.1</jackson.version>
     <slf4j.version>2.0.6</slf4j.version>
+    <log4j.version>2.19.0</log4j.version>
   </properties>
 
   <build>
@@ -133,8 +134,15 @@
     <dependency>
       <groupId>org.apache.logging.log4j</groupId>
       <artifactId>log4j-core</artifactId>
-      <version>2.19.0</version>
+      <version>${log4j.version}</version>
     </dependency>
 
+    <dependency>
+      <groupId>org.apache.logging.log4j</groupId>
+      <artifactId>log4j-api</artifactId>
+      <version>${log4j.version}</version>
+    </dependency>
+
+
   </dependencies>
 </project>