Commit Briefs
mailmux: use builtin sqlite datetime functions to set modtime
Better to use the functionality provided by sqlite since we've decided to bring on the dependency. Might as well use it.
mailmux: store last modified time of users, aliases
This is useful information that could be used for auditing people abusing the service, some basic non-invasive system metrics, and of course it's useful for users to see in the interface.
mailmux: limit registration request/response sizes
Hopefully this will prevent any abuse from causing too many problems!