Add imagePullSecrets (#630)

* Add imagePullSecrets

* Remove pull secrets from template

imagePullSecrets is set one level higher than this template, and not
directly on the container definition.

Replace clickhouse backup cron with single imagePullSecrets

Replace clickhouse_instance with single imagePullSecrets

Add imagePullSecrets to eventrouter

Add imagePullSecrets

* Add pullSecrets to our other deployments

These already supported imagePullSecrets, and I don't want to remove the
field in case that breaks a deployment elsewhere.

So, support both :/

* Add .root

* Add tests for web, worker, migrate, events

* Add tests for plugin deployments

* Bump chart version

Co-authored-by: Ellie Huxtable <ellie@posthog.com>

Author: guidoiaquinti

charts/posthog/Chart.yaml

@@ -11,7 +11,7 @@ type: application
 
 # This is the chart version. This version number should be incremented each time you make changes
 # to the chart and its templates, including the app version.
-version: 29.0.7
+version: 29.0.8
 
 # This is the version number of the application being deployed. This version number should be
 # incremented each time you make changes to the application.