Collapsible category and tag selectors

To help minimise the clutter on template settings pages, we have introduced collapsible sections to better manage categories and tags. 

Some hubs use many categories to help organise templates, which can be daunting when viewed all at once. This feature will help make that easier and only display what is necessary. 

With this update, selecting a subcategory will automatically select the parent category so they will always be connected.