Improve Operations grimoire old content query

Summary:
The last Rhyne-Wyse diff showed two issues with the current query:

• report content NetBox and Netbox, one the page, one the redirect
• order of pages for a same age isn't deterministic

Ignore redirects and sort first by the age, then by title.

This is a follow-up for 3c94fd688d3e.

Test Plan: run-report agora-operations-grimoire-older-pages

Reviewers: dereckson

Reviewed By: dereckson

Differential Revision: https://devcentral.nasqueron.org/D3695