Allows users to override the language-level date and time format settings.
Adds two new User Custom Fields:
Preferred Date Format
All (non-custom) formats from the admin panel
Full-year m/d/y and d/m/y formats
ISO 8601 YYYY-MM-DD format
Preferred Time Format
12 and 24 hour formats
They are both optional and apply individually. A user who does not select an option will get the setting defined in their selected language for that field.
If you do not wish to allow selection of both...
