- Outer loop for sweep file
- Inner loop for measurement (can be called as a separate function)
- Each measurements has its own csv file

- Load VNA config (and calibration) from file.
  The *.znxml file has to be prepared in advance and saved on the VNA.
  It needs to set the VNA to CW mode and single sweep.
- Trigger single sweep and wait for it to complete
- Fix trace definitions

- Frequency is a new parameter in json file
- Set wide acceptance ranges of other test stand parameters for demo purposes

Ploting window is now in PDF format not in png format

plot is now saving with CSV file with same name .It doesnt pop up now after reading.

Works correctly for failing and working stable condition during the
measurement phase, but does repeat yet when it fails.

Also did code cleaning

read_data now returns a data class instead of a list

- mostly whitespace and linebreaks
- no functional change