Extend Observations endpoint for more effective data transfer in MaTS

In MaTS we synchronize the data from our influx & timescale DB to STA. The current implementation uses the Observations Endpoint for that. That works but the restrictions of maximum of 100 Observations currently makes the processing rather slow.

So there is the need to adjust the Observations endpoint in a way that supports to query for a larger count of elements - and that would allow pagination additionally.