Adds a date picker for SQL reports with the 'date' authorised_value. Updates help
documentation for this new feature, as well.
To test:
1. Create a new report with two date parameters, using the syntax:
<<Label for this selection of date|date>>
2. Run the report
3. Select dates
4. The SQL generated should format the dates properly in ISO, and keep track of which
date is which
Signed-off-by: Jared Camins-Esakov <jcamins@cpbibliography.com>
08b7589b85