As a developer, I want to use a REST Client to populate the choose dialog of a link fieldtype, so that I can enable linking to external content, and don't have to configure the same REST config in multiple places.

For example, a link field opens a choose dialog to display the products in an external Product Information Manager system.

Acceptance Criteria:

• A link fieldType can open a chooser dialog which displays a list of external content,  via a REST Client.
• Specify the REST Client to use via configuration and light development. No Java development is necessary.