Grammar refactoring

* Grammar refactoring WIP

* ISerializer.grammar

* Fixing various bugs in the grammar

* Small touch that improoves performance

* Fix unknown values grammar

* Various fixes

* Serialization refactoring to drop suboject logic

* Details fixed

* Entity attributes initialization refactoring

* JSDoc error fixed

* Rename value key to default

* Remove useless default

* Revert string keys

js/entity/LocalizedTextEntity.js

@@ -5,9 +5,15 @@ export default class LocalizedTextEntity extends IEntity {
 
     static lookbehind = "NSLOCTEXT"
     static attributes = {
-        namespace: "",
-        key: "",
-        value: "",
+        namespace: {
+            default: "",
+        },
+        key: {
+            default: "",
+        },
+        value: {
+            default: "",
+        },
     }
 
     static {