Update Labour to get specific properties when getting person

[tamuri]

Profiling finds that repeated df.loc[[person_id]], where all properties are retrieved, is a bottleneck in the Labour module. This PR updates the module to only retrieve those properties necessary.

Joe - although each labour linear model only uses a few of these properties, grabbing everything necessary for all of them is an easy change for now.

I'm running profiling again to see if further improvements can be made.

[tbhallett]

This makes good sense to me.

[tamuri]

Trying a different approach to speed this up further. This is has reduced runtime of predict from 4% to <0.3%

A decorator person_properties in labour_lm adds metadata to the function specifying exactly which person properties from the population dataframe (if any) are needed to evaluate the function. If nothing it needed, it is set to an empty list.

The labour module uses this metadata to grab only those specified properties from the population dataframe.

Sometimes the required modules are not available and we have to remove their properties from the list.

Sorry, @tbhallett @joehcollins, do you mind looking at this again.