This patch switches the externalTrafficPolicy to `Local` for the
proxy-protocol enabled services, in order to skip kube-proxy when
connecting, this makes sure that proxy-protocol can actually function
and doesn't hit a node that would need to redirect traffic.

References:
https://metallb.org/usage/#layer2
https://github.com/kubernetes/kubernetes/issues/66607
https://github.com/digitalocean/digitalocean-cloud-controller-manager/pull/206

This patch disables error queries from zenhaus. It requires some more
tinkering down the line, but should accept email for now.

This patch replaces the individual helm chart gitlab-ci yamls with a
common gitlab-ci yaml for all charts, that will trigger based on changes
and allow more generalised and unified CI jobs for all charts.

This patch allows to set the `HOSTNAME` variable, which should
explicitly set the hostname for the postfix pod and configure it to use
the proper external DNS name.

DNSWL went subscriber-only apparently.

References:
https://www.dnswl.org/

This patch is a workaround for gitlab jobs that merge themselves by
accident. it should be further refined, similar to the images setup to
have a more generalised pipeline in the future.

This patch fixes the absense of persistence for sieve rules, due to
being layed out in parallel to the `/srv/mail/mailbox` directory in the
dovecot container.

By moving the mountpoint to `/var/mail` the sieve rules should be
persisted along the way with the mailboxes.

BREAKING CHANGE: This patch adjusts the mount location for mail data,
which will require manual interaction.

Due to a copy-paste mistake, dovecot was using the postfix replicaCount
for its own. This is obviously not intended and was fixed by this
commit, correcting the snapshot and adding obviously needed tests to
prevent such a mistake in the future.

This patch deployes the fixed postfix image containg postscreen with
enabled smtpd.

This patch creates a PDB for postfix, if the setup is scaled to more
than 1 postfix replica. This way at least one postfix instance should
always be available and the MTA therefore HA.

Currently the dovecot backend is not yet HA, this should take place
later on.

Currently each update of the application version requires an update of
the snapshot, this is annoying and doesn't help the chart with anything.
Therefore this patch enforces a chart version for all snapshot tests and
also stablizes the config reload hash magic regarding versioning
changes.

Currently postfix reports and error due to the missing service. This
patch fixes the problem by enabling the expected service in master.cf

This patch should enable the postfix setup in MoK to utilise the
proxy-protocol and therefore gather required IP information from
connecting clients.

It's implemented based on some documentation regard the topic and is
useful for reverse-proxy setups e.g. behind haproxy.

References:
https://www.haproxy.com/blog/efficient-smtp-relay-infrastructure-with-postfix-and-load-balancers/

This patch adjust the helm package command to only package the actually
changed chart an not double upload packaged helm charts.

This patch adds the common config reload annotation trick to the MoK
helm chart, which should make sure that new users are picked up
immediately.

References:
https://helm.sh/docs/howto/charts_tips_and_tricks/#automatically-roll-deployments

Currently the service name for dovecot was hardcoded in the image, which
makes it incompatible with MoK. As a result this patch updates the image
to allow a dynamic overwrite on startup as well as updating MoK to
account for the new functionality.

This patch adds the needed network policies to the helm chart. This
provides a reasonable base-line setup. Currently any customizations
regarding network access would require additional policies. These might
come in place later on.

Adding a new helm chart to deploy functional mail server on Kubernetes.
It's composed of postfix and dovecot so far and handles user management
using Kubernetes secrets.