Added RBAC for REST APIs.

- admin role required for POST, PUT, DELETE & PATCH
- viewer role required for all other requests
- cleaned up all web.xml files for consistency and correctness

Change-Id: I33bad5cec0fb0f4285eed84173025b0a107b5aec
diff --git a/utils/rest/src/main/java/org/onlab/rest/AbstractWebApplication.java b/utils/rest/src/main/java/org/onlab/rest/AbstractWebApplication.java
index f744929..41839c7 100644
--- a/utils/rest/src/main/java/org/onlab/rest/AbstractWebApplication.java
+++ b/utils/rest/src/main/java/org/onlab/rest/AbstractWebApplication.java
@@ -19,6 +19,7 @@
 import com.google.common.collect.ImmutableSet;
 import org.onlab.rest.exceptions.BadRequestMapper;
 import org.onlab.rest.exceptions.EntityNotFoundMapper;
+import org.onlab.rest.exceptions.ForbiddenMapper;
 import org.onlab.rest.exceptions.IllegalArgumentExceptionMapper;
 import org.onlab.rest.exceptions.IllegalStateExceptionMapper;
 import org.onlab.rest.exceptions.NotFoundMapper;
@@ -43,7 +44,9 @@
      */
     protected Set<Class<?>> getClasses(Class<?>... classes) {
         ImmutableSet.Builder<Class<?>> builder = ImmutableSet.builder();
-        builder.add(ServiceNotFoundMapper.class,
+        builder.add(AuthorizationFilter.class,
+                    ForbiddenMapper.class,
+                    ServiceNotFoundMapper.class,
                     EntityNotFoundMapper.class,
                     NotFoundMapper.class,
                     ServerErrorMapper.class,