R1:0854425d191f

When printing timestamps on paper: use an absolute, context-free date format

Summary:
Ref T13573. Using the browser "Print" feature on pages produces "Thu, Aug 4, 12:22" timestamps which require context to interpret precisely (they don't have a year and don't have a timezone).

Instead, retain these timestamps in "screen" contexts but use "YYYY-MM-DD HH:MM:SS (UTC+X)" timestamps when printing.

Test Plan: Printed Maniphest tasks and other pages in Safari and Chrome using "?__print__=1" and "Print to PDF"…