Switch to Tomcat 9.0.104 dependencies

This is the last (maintained) version still compatible with Java 8.
Compare with https://tomcat.apache.org/whichversion.html.

This closes #807

Author: kwin

accesscontroltool-bundle/pom.xml

@@ -24,7 +24,7 @@
     <description>The OSGi bundle containing all classes of the Access Control Tool.</description>
 
     <properties>
-        <tomcat.el.version>10.0.27</tomcat.el.version>
+        <tomcat.el.version>9.0.104</tomcat.el.version>
         <oak.testing.version>1.48.0</oak.testing.version><!-- ITs require a newer version of Oak otherwise it won't work with Java 11 and certain classes for running the IT are not available -->
     </properties>