Update /surveyedlocale endpoint to enable datapoint filtering

[muloem]

As part of the updates to the assignments (see #2796) that enable selecting specific datapoints to assign them to devices (#3166), we need to modify the endpoint used by devices to download datapoints, to enable it filter out and only return datapoints assigned to a specific device.

Some issues to consider:

• If we return such a filtered list, would it be processed without any problems by devices with current versions of the app?

[stellanl]

To avoid backwards-compatibility problems we decided to add a new endpoint, /datapoints that will return only the data points (surveyedLocales) the device has been assigned. It generally uses the same parameters as /surveyedlocale.

Old apps continue to use the old endpoint and get all data points as before.

[janagombitova]

I guess there is nothing user-facing to test for this specific issue for now, right? Is this change on UAT1? Can we close the issue?

[janagombitova]

All linked PRs are merged and released. If this still needs work - please reopen