Multi: Update maintenance timings + disable usercache
Multi: Update maintenance timings + disable usercache

The usercache maintenance cron is causing significant downtime each
month, so I've disabled it for now.

christian-roggia/vndb,morkt/vndb,morkt/vndb,christian-roggia/vndb,morkt/vndb,erengy/vndb,morkt/vndb,christian-roggia/vndb,erengy/vndb,morkt/vndb,erengy/vndb