Added a URI parameter 'type' for GET /v1/contextEntities

### Description
GET /v1/contextEntities now supports the URI parameter 'type'.
Complete with functional test.

Yeah, I will make a function of it, and perhaps I can move it up to a common place.
Let's make it 'perfect' for this operation first and after that we start thinking of the others.

I noticed myself I missed the brackets and I have fixed it already, but for the nextcoming PR.