This commit adds two new getters to the category model:
- `displayName`
- `descriptionText`
These getters are used instead of `name` and `description_text` where appropriate.
On top of this two transformers have been added to allow plugins to alter these getters:
```javascript
api.registerValueTransformer(
"category-display-name",
({ value, context }) =>
value + "-" + context.category.id + "-transformed"
);
```
```javascript
api.registerValueTransformer(
"category-description-text",
({ value, context }) =>
value + "-" + context.category.id + "-transformed"
);
```
