Make `maxNOR` part of `decectorSettings` in the survey

[han16nah]

Problem

maxNOR is currently a scanner setting defined in the scanner XML file. However, the maximum number of returns per pulse often depends on the power (and pulse frequency) and is therefore not a fixed value for one scanner.

Solution

It should be possible to overwrite the maxNOR from the survey file as part of the detectorSettings. Similarly, it should be possible to specify a reduced power level in the survey (e.g., by providing a percentage).