Parametrized combinators

[augustinas]

Suggestion from Chris Pointon

To reduce the code complexity and the load on the DS backend, can I propose parameterized combinators as a future enhancement?

e.g.

[
  {
    "endpoint": "rumpel/locations",
    "filters": [
      {
        "field": "data.locations.timestamp",
        "transformation": {
          "transformation": "datetimeExtract",
          "part": "hour"
        },
        "operator": {
          "operator": "between",
          "lower": "$lower",
          "upper": "$upper"
        }
      }
    ]
  }
]

The call to get the result would then be:
GET /api/v2.6/combinator/$COMBINATOR_NAME?lower=7&upper=9