KEYCLOAK-19374 Create implementation based on annotation processor

Use of boxed types as started in 009d4ca445 is finalized here
to enable storing data in a map. MapClientEntity methods are
reordered for the sake of grouping the collection-based
properties together and understanding the connections between those.

model/pom.xml

@@ -34,5 +34,6 @@
         <module>jpa</module>
         <module>infinispan</module>
         <module>map</module>
+        <module>build-processor</module>
     </modules>
 </project>