SEC-2098, SEC-2099: Created HeadersFilter

Created HeadersFilter for setting security headers added including a
bean definition parser for easy configuration of the headers. Enables
easy configuration for the X-Frame-Options, X-XSS-Protection and
X-Content-Type-Options headers. Also allows for additional headers to
be added.

samples/contacts/src/main/resources/applicationContext-security.xml

@@ -30,6 +30,12 @@
         <http-basic/>
         <logout logout-success-url="/index.jsp"/>
         <remember-me />
+        <headers>
+            <xss-protection />
+            <frame-options policy="DENY" />
+            <content-type-options/>
+            <header name="foo" value="bar"/>
+        </headers>
         <custom-filter ref="switchUserProcessingFilter" position="SWITCH_USER_FILTER"/>
     </http>