As a developer I want to fetch the data of a property, so I can use elements I need in my application
GET /entities/properties/{property_id}
Can be seen as a counterpart of GET /entities/items/{item_id}
The structure of data in response will be similar to item data structure with additional top-level `data-type` field carrying the data on the property's data type. There will be no `sitelinks` field and the Action API's `claims` field will be renamed to `statements`.
Note:
* authentication and authorization - same treatment as existing for GET item data endpoint.
* sitelinks do not exist on properties
* redirects do not exist for properties
To not include in this story (will be done later on)
* handling conditional HTTP headers
* `_fields` parameter to define what property data elements to include in the API response
Error cases to consider:
<table>
<tr>
<th>error type</th>
<th> HTTP Response code</th>
<th>Response content</th>
</tr>
<tr>
<td>Property with the given ID does not exist</td>
<td>404</td>
<td>
`"code": "property-not-found",`
`"message": "Could not find a property with the ID: '{property_id}'"`
</td>
</tr>
<tr>
<td>ID provided is not a valid property ID</td>
<td>400</td>
<td>
` "code": "invalid-property-id",`
`"message": "Not a valid property ID: '{property_id}'"`
</td>
</tr>
</table>
Any authentication/authorization errors -- rely on the behaviour of the Mediawiki REST API "framework".