Feature request: add extra information to the output

[pkiraly]

A request came from Deutsche Digitale Bibliothek to add extra information into the output (CSV file). The easiest way to do this is to create a new AnnotationCalculator, which simply emits the information which the user sets by methods of the MeasurementConfiguration:

void setAnnotationConfiguration(String json)
void setAnnotationConfiguration(Map<String, Object> annotations)
MeasurementConfiguration withAnnotationConfiguration(String json)
MeasurementConfiguration withAnnotationConfiguration(Map<String, Object> annotations)

In both cases the input should be a key-value pair, where the key is a string, a value is a string, or a number (integer or double).

The output will simply contain the input among the columns or fields.