Store/Retrieve order templates in new order-templates API

Overview

Order templates are currently stored in mod-configuration, but they're being moved to the orders app. As such, the various places that save/retrieve/manage order templates (settings as well as order/poLine forms) need to be updated.

NOTE: the new API will return json not a string.

Acceptance Criteria

• update dependency/permissions (if needed)
• order templates section in settings use the order templates API in mod-orders
• create/edit/details order and poLine views use the order templates API in mod-orders
• tests are updated