Function names and labels do not always match

Currently not all the labels match their respective function names e.g. "average_values" (function name) but result is saved under "mean" (label).

List of mismatched function names and labels:

function name	label
value_count	count
average_values	mean
standard_deviation	stddev
maximum	max
minimum	min
perc<dd>	p<dd>
max1h_values	max1h

Exceptions:

• percentils1, percentiles2 - they call multiple perc<dd> functions and use their respective labels
• nvgtall - calls multiple nvgt<ddd> functions and use their respective labels