Create `GET /detections/summary` and `GET /classifier-jobs/{jobId}/best-detections/summary`

Is your feature request related to a problem? Please describe. ~~Currently the GET /classifier-jobs/{id}/summary is being used in this given UI (link below). https://www.figma.com/file/FGnP9kAFLDmraAFJf8OBAG/CNN-Roadmap?type=design&node-id=97-857&mode=design&t=zgf5wKqMLTe1cJoj-4~~

~~We would also like to use this API for this portion of the UI https://www.figma.com/file/FGnP9kAFLDmraAFJf8OBAG/CNN-Roadmap?type=design&node-id=337-5942&mode=design&t=zgf5wKqMLTe1cJoj-4~~

We are creating 2 new endpoints to serve this data from the Core API.

Then we can call this API to just grab information about counts

Describe the solution you'd like We would like to create 2 new endpoints to serve information about the counts of each validation status based on given query parameters. The 2 new endpoints are

GET /detections/summary. Which will have the exact same query parameter as GET /detections
GET /classifier-jobs/{jobId}/best-detections/summary. Which will have the same query parameter except by_date.

The return type of the API will be

{
  "unreviewed": 1815,
  "rejected": 122,
  "uncertain": 0,
  "confirmed": 18
}

This task will able to be closed when these 2 subtasks are finished

[x] #593
[x] #595

Describe alternatives you've considered none

Additional context none

rfcx / rfcx-api

Create `GET /detections/summary` and `GET /classifier-jobs/{jobId}/best-detections/summary` #592