R1:88caa4585413

Save daemon state to database

Summary:
To make it easier to monitor daemons, let's store their current state
(running, died, exited, or unknown) to the db. The purpose of this is to
provide more information on the daemon console about the status of daemons,
especially when they are running on multiple machines. This is mostly backend
work, with only a few frontend changes. (It is also dependent on a change
to libphutil.)

These changes will make dead or stuck daemons more obvious, and will allow
more work…