Feature request: API v2 lookup context_annotations #19

The context_annotations field in tweets has extreme potential for us developers and researchers to understand the interests of a user, build communities, improve recommendation algorithms, etc, etc.
As far as I understand, an entity has a unique id and can belong to one or many domains (please correct me if I'm wrong). I think an endpoint to get information about a specific entity would be very useful.

Eg: GET /2/context_annotations/entity/:id would return a JSON with the fields:

{
    "id": "XXXX", 
    "name": "XXXX", 
    "description": "XXXX", 
    "domains": [
         {
             "id": "XXXX",
             "name": "XXXX", 
             "description": "XXXX"
         }
    ] 
}

Could be future proof for things like associated_users or something like that. Thought about receiving some opinions and feedback before opening a formal request (as per the indications in README).