We need an auto-suggest widget where the choices offered will be P-items limited to a particular data type - e.g. P-items beginning with 'ca' whose values are Q-items (excluding P-items whose values are quantities, geo co-ordinates, etc)
Why do we need it?
* We're planning to support adding arbitrary statements to files on commons - a user can choose an arbitrary property, and give it a value. In order to be able to deliver incrementally we need to implement this one data type at a time (initially we'll only be supporting properties with data type `wikibase-entity`), so we need to be able to limit the properties that a user can choose to a particular data type
How are we going to build it?
2 possible approaches:
* filter out data types we don't want from `wbsearchentities` responses on the client side, and make additional requests if we don't have enough data (using the continue param)
* modify `wbsearchentities` so that it accepts data-type as a param, and filters on the server side
Acceptance Criteria:
[] I can use `wbsearchentities` from a js autosuggest to display to the user matching wikidata properties limited to 1 or more data types