Move all front-end public field definitions into constructors for iOS support

app/assets/app/cobalt/Form.component.js

@@ -146,20 +146,24 @@ export default class FormComponent extends Component {
         return ['resource', 'form_id', 'initial_mode']
     }
 
-    definition = {}
-    data = {}
-    uuid = ''
-    title = ''
-    error_message = ''
-    other_message = ''
+    constructor() {
+        super()
 
-    access_msg = ''
-    can_access = false
+        this.definition = {}
+        this.data = {}
+        this.uuid = ''
+        this.title = ''
+        this.error_message = ''
+        this.other_message = ''
 
-    is_ready = false
-    mode = ''
-    id = ''
-    t = {}
+        this.access_msg = ''
+        this.can_access = false
+
+        this.is_ready = false
+        this.mode = ''
+        this.id = ''
+        this.t = {}
+    }
 
     reset() {
         this.definition = {}

app/assets/app/cobalt/Listing.component.js

@@ -65,13 +65,17 @@ export default class ListingComponent extends Component {
     static get template() { return template }
     static get props() { return ['resource'] }
 
-    definition = {}
-    data = []
-    resource_class = {}
+    constructor() {
+        super()
 
-    access_msg = ''
-    can_access = false
-    t = {}
+        this.definition = {}
+        this.data = []
+        this.resource_class = {}
+
+        this.access_msg = ''
+        this.can_access = false
+        this.t = {}
+    }
 
     async vue_on_create() {
         this.t = await T(