feat(KeyType): Add AssignedKey Type

`AssignedKey` types do not set or retrieve any values from the database.
Another name for this key type would be `NullKeyType`.

models/KeyTypes/AssignedKey.cfc

@@ -0,0 +1,19 @@
+component implements="KeyType" {
+
+    /**
+     * Called to handle any tasks before inserting into the database.
+     * Recieves the entity as the only argument.
+     */
+    public void function preInsert( required entity ) {
+        return;
+    }
+
+    /**
+     * Called to handle any tasks after inserting into the database.
+     * Recieves the entity and the queryExecute result as arguments.
+     */
+    public void function postInsert( required entity, required struct result ) {
+        return;
+    }
+
+}