Expand functionality on /api/v3/data/topn endpoint to consider custom timespan like in NMS Web UI

The /api/v3/data/topn endpoint accepts a variety of parameters (aggregation unit, device filters, sorting, etc.), but it does not include a timespan selection. While the API response does include a label attribute (e.g., "Today") and a timeRanges object with start/end timestamps, these appear to be read-only and do not reflect user-defined intervals.

The endpoint should consider a parameter to define a custom time range (e.g., startTime and endTime, or a predefined interval like LAST_7_DAYS), proper handling of the timeZone parameter -or inference from it by the user preferences from the API key used- to ensure accurate reporting for users in different time zones.

This behavior can be evidenced by running a request and noticing the result from a simple query like in the example, will default using UTC 00:00 to ~3:44 in this example:

# /api/v3/data/topn?aggregationUnit=AGGREGATION_AUTO&capacityThreshold.operator=OPERATOR_NONE&devices.ids=25&deviceGroups.ids=542&deviceGroups.membership=MEMBERSHIP_ANY&objectGroups.membership=MEMBERSHIP_ANY&sort=SORT_DESCENDING&templateId=1&units.percentage=PERCENTAGE_ALL&units.preferred=PREFERRED_BYTES

{
  "partialResults": null,
  "rows": [],
  "timeRanges": [
    {
      "specificInterval": {
        "startTime": 1778284800,
        "endTime": 1778298293
      },
      "timeZone": "",
      "label": "Today"
    }
  ]
}