Feature/latest endpoints

[russbiggs]

Adds endpoints for /v3/locations/{locations_id}/latest and /v3/parameters/{parameters_id}/latest. Both have a datetime_min filter which allows users to filter out latest measurements that are older that the provider datetime or date. This query param uses the same structure and rules as the datetime_from, datetime_to query params.

This creates a new response model, Latest which looks like:

{
  "datetime": {
    "utc": "2024-08-26T22:00:00Z",
    "local": "2024-08-27T00:00:00+02:00"
  },
  "value": 14.879166841506958,
  "coordinates": {
    "latitude": 51.966058631890675,
    "longitude": 6.289890937160651
  },
  "sensorsId": 9074015,
  "locationsId": 2827201
},

[caparker]

Looks great. I did add some more tests. Some unit tests for the new datetime min query param and then some sql tests for the latest endpoints - all passed without modification.