Bug#905204: Add support for reminding page authors to update content periodically

[Steve McIntyre <steve@einval.com>]

Package: wiki.debian.org
Severity: wishlist

An idea I've had for a while but not yet implemented properly. Here as
a reminder...

Add support for extra metadata (CategoryXXXX) to mark pages as needing
checking/updating after a specified period (e.g. 3w, 6m, after a new
major Debian release). Then we can add a script to walk the wiki page
data periodically and mail people (the last page editor?) when pages
are outdated.

-- System Information:
Debian Release: 9.5
  APT prefers stable-updates
  APT policy: (500, 'stable-updates'), (500, 'stable-debug'), (500, 'stable')
Architecture: amd64 (x86_64)
Foreign Architectures: i386

Kernel: Linux 4.9.0-7-amd64 (SMP w/4 CPU cores)
Locale: LANG=en_GB.UTF-8, LC_CTYPE=en_GB.UTF-8 (charmap=UTF-8), LANGUAGE=en_GB.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)