Standardise date formats in data-source model when constructing query string
Standardise date formats in data-source model when constructing query string

By having a single place to normalise dates we can avoid having to care about it anywhere else. We can pass dates in any valid format, and the model will magically parse them into ISO8601

keithiopia/spotlight,keithiopia/spotlight,tijmenb/spotlight,tijmenb/spotlight,keithiopia/spotlight,alphagov/spotlight,alphagov/spotlight,alphagov/spotlight,tijmenb/spotlight