Get max data points limit (getMaxDatapointsLimit)

Get the maximum number of data points that dashboard may request from the server per in a single subscription command. This value impacts the time window behavior. It impacts 'Max values' parameter in case user selects 'None' as 'Data aggregation function'. It also impacts the 'Grouping interval' in case of any other 'Data aggregation function' is selected. The actual value of the limit is configurable in the system configuration file.