This patch reworks the Pod rolling mechanism, which is supposed to update Pods
with each migration run, but since the it generates a new random value on each
helm execution, this will constantly roll all pods in a GitOps driven deployment,
which reconciles the helm release.

This is resolved by fixing the upgrade to the `.Release.Revision`, which should
stay identical, unless config or helm release version have been changed. Further
it introduces automatic rolls based on adjustments to the environment variables
and secrets.

The implementation uses a helper template, following the 1-2-N rule, and omitting
code duplication.

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

* Revert "Fix helm chart use of Postgres Password (#19537)"

This reverts commit 6094a916.

* Revert "Fix PostgreSQL password reference for jobs (#19504)"

This reverts commit dae954ef.

* Revert "Fix PostgreSQL password reference (#19502)"

This reverts commit 9bf6a8af.

* Correct default username in postgresql auth

Fixes #19536

* Add ability to specify an existing Secret (#18139)

Closes #18139

* Allow using secrets with external postgres

* Upgrade CronJob to batch/v1

* Allow using redis.auth.existingSecret

* Helmignore mastodon-*.tgz for easy local development

* Upgrade helm dependencies

* Upgrade postgresql to 11

* Allow putting SMTP password into a secret

* Add optional login to SMTP secret

This to allow setting LOGIN either in values.yaml or
in the secret.

* Switch to bitnami charts full archive

This prevents older versions from disappearing, see
https://github.com/bitnami/charts/issues/10539

 for
full context.

Co-authored-by: Ted Tramonte <ted.tramonte@gmail.com>

- move application variables under `mastodon` namespace
- restore standard yaml structure for ingress configuration
- move values.yaml.template to values.yaml

* add Helm chart

known issues/future work:

- SSO is unsupported

- S3/Minio/GCS is unsupported

- Swift is unsupported

- WEB_DOMAIN is unsupported

- Tor is unsupported

* helm: clarify how LOCAL_DOMAIN is set

* helm: add chart description

* helm: make DB_POOL and Sidekiq concurrency configurable

* helm: only enforce pod affinity when using ReadWriteOnce

* helm: clarify compatibility

* helm: clean up application variables

* helm: add job to create initial admin