New *RecentChanged similar to *RecentAdded

[simoncn]

Based on the experience of implementing Recently Added and Recently Played, it would be a significant amount to work to add a Recently Changed index that works in a similar way.

The simplest way to enable browsing by most recently changed date would be for MinimServer to add a new "special tag" (see this section). The tag name would be Last Modified (#LastModified in indexTags) and its value would be the file system "last modified" date in the format yyyy-mm-dd. The default sort order in the Last Modified index would be most recent first. All files (including added files) would have this tag (if enabled via indexTags), not just a limited number of recently modified files.

I would welcome comments from other users about whether this would be a useful addition to MinimServer and how they would use this tag if it were added.