Introduce a new field to report on non-operational energy consumption `en_abs_nopr_ev`

Addition of a field to report on non-operational electric vehicle charging station consumption. The object is en_abs_nopr_ev within the annual_data array. This means you can now split this non-operational consumption from your overall consumption.

Update the https://github.com/GRESB/api-docs/blob/master/data/dictionary.yml.
Ensure that it flows into the Ruby wrapper which reads the yaml file: https://github.com/GRESB/api-docs/blob/master/source/includes/_data-dictionary.md.erb.
Update the request examples in https://github.com/GRESB/api-docs/blob/master/source/includes/_assets.md

GRESB / api-docs

Introduce a new field to report on non-operational energy consumption `en_abs_nopr_ev` #158