After thinking for a little while I actually think the body of a post
may be more relevant when searching for posts than the thread title.
Right now this is just a hunch and we'll have to find out how it
actually ends up working in real life.
Adds a 'sticky' column to threads and rewrites the thread index to
take sticky markings into account when ordering threads.
Stickies are not yet highlighted in any way in the forum overview.
Adds columns for author names and emails to both threads and posts.
"Users" don't (yet? who knows!) exist as independent entity in
Converse, they are simply "inferred" via OIDC providers.
