In case of TLS_FLAVOR=[mail,cert], the user supplies their own certificates.
However, since nginx is not aware of changes to these files, it cannot
reload itself e.g. when the certs get renewed.
To solve this, let’s add a small daemon in the place of
`letsencrypt.py`, which uses a flexible file-watching framework and
reloads nginx in the case the certificates change ….
- Specified seperated /health path in order to allow for healthcheck even if webmail and admin are not seletectd. This also allows healthchecking fom external services like DNS load balancers;
- Make curl not to fail on TLS because localhost is not included in the certificates.
