Add format for description column to control number of annotations shown

I was importing/syncing some tasks from gerrit using bugwarrior, with comments pulled in as annotations, which got very long especially with CI adding in comments about failed runs e.g.,. It got me thinking that having a format option available for description which showed, e.g., the most recent or least recent N annotations.

This would enable users to show recent/relevant annotations, which serves a dual purpose of shortening the length of the description and maintaining some level of context with respect to the annotations (e.g., a link to the bug/ticket).

No new reports would be needed, this would be a feature for reports, though I imagine no default functionality would need to change.

I might take a crack at it some weekend, but figured I'd throw the issue in here in case someone else is interested in the functionality!

Thank you for your work on taskwarrior :)