Always store CSRF token for each page in Vue.js theme

so child components don't have to "redefine" it.  at least, those that know
about the page already having it...

tailbone/templates/page.mako

@@ -35,7 +35,10 @@
         methods: {}
     }
 
-    let ThisPageData = {}
+    let ThisPageData = {
+        ## TODO: should find a better way to handle CSRF token
+        csrftoken: ${json.dumps(request.session.get_csrf_token() or request.session.new_csrf_token())|n},
+    }
 
   </script>
 </%def>