OZP-737: Externalize OWF and Rest security context xml files.

1. Removed OWFsecurityContext.xml and RESTsecurityContext.xml files, along with their respective beans, from inside the wab and rest bundles to a separate security bundle.
2. Modified their applicationContext.xml files to point to the new location of the context files in ${server.home}/etc/security, where server.home will be set to catalina.home in tomcat and karaf.base in enterprise.
3. Moved maven-assembly-plugin configuration down a pom so the security bundle will have access to it.