Admin: No annual review for sites which haven't changed in a year

[m-i-l]

It would be good to only list sites which have changed in some way for the annual review.

As background, after the popularity of https://blog.searchmysite.net/posts/almost-all-searches-on-my-independent-search-engine-are-now-from-seo-spam-bots/ in mid-May 2022, there were several hundred new site submissions. These came up for annual review in mid-May 2023, and again in mid-May 2024. It takes a considerable time to review several hundred sites, and by mid-May 2024 most sites didn't look like they had been updated since 2022.

Probably still want old content in the system in case there is anything useful there. But any form of content change should still require review, to e.g. identify any domains which have been taken over and are no longer personal sites, or sites which have gone offline.

Will need #95 to be implemented first. Could simply automatically approve the annual review and set the user performing the annual review to be admin, or something like that.