GUACAMOLE-736: Replace JAXB DatatypeConverter with Guava BaseEncoding.

guacamole/pom.xml

@@ -493,6 +493,13 @@
             </exclusions>
 
         </dependency>
+        
+        <!-- Guava Base Libraries -->
+        <dependency>
+            <groupId>com.google.guava</groupId>
+            <artifactId>guava</artifactId>
+            <version>27.0.1-jre</version>
+        </dependency>
 
     </dependencies>