Add Date and Time format select to Post Display Settings

postponed on #216961: Make author/submitted by separate toggles
and related to comments #70-#74 on #143434: Usability Issue: Post Information Settings

Allow a (drop down) configuration option to pick the format of the date displayed for the publication date.
in D6, admin/settings/date-time/formats, Admin -> Site Configureation -> Date and Time
has a setting allowing the creation of new Date formats. It would be cool to make a "Book Year" format, and on content types for Book, be able to pick that format for displaying the publication date in the post settings.

So for each content type:

Display Settings:
[ ] Display authors username
[ ] Display creation date
--- Select date format: [drop down: long, short, etc. ] (?)

The Select could be disabled or grayed out if the display date is unchecked.

And the (?) help would open up a link to the Admin Date and Time settings page and include a statement like: Change current date and time formats or create a new format.