notify: Send all sd_notify signals from main caddy process (#4060)

Initial sd_notify support was added in #3963, but that sent signals from
both cmdRun and cmdReload.  This approach has two drawbacks:

- Reloads initiated via the API do not send signals.
- The signals are sent from different processes, which requires the
  `NotifyAccess=exec` directive in the unit file.

This change moves the NotifyReloading and NotifyReadiness invocations to
Load, which address both of those drawbacks.  It also adds a
complimentary NotifyStopping method which is invoked from handleStop.
All the notify methods are defined in a notify package to avoid an
import loop.

0 files changed, 0 insertions, 0 deletions