Abstract commonalities from Picker Components

[knittingdev]

All picker components use a similar template, it'd be easier to maintain the pickers if we could abstract out the boiler plate functionality (instantiating the date range picker dependency) so that individual pickers can focus on what makes them unique (picking date/month/year).

I believe the simplest way to accomplish this is by making the Picker Mixin and component that all pickers extend from.