Patch Notes: Faster town seats

Online services

• Town seats are now worked out once a minute for the whole server, not by every server process on every request. The seats list, Watch claims, Levies, Tithes and sieges load faster and put far less strain on the database.

What's Changed

• SEAT-FACTS: the minute's clock keeps the seats' facts in one row; every isolate reads it by @Lattymoy in #888

Full Changelog: app-v0.1.8523...app-v0.1.8525