Propagate annotations to the StatefulSet (#932)

* Initial commit

* Corrections

- set the type of the new  configuration parameter to be array of
  strings
- propagate the annotations to statefulset at sync

* Enable regular expression matching

* Improvements

-handle rollingUpdate flag
-modularize code
-rename config parameter name

* fix merge error

* Pass annotations to connection pooler deployment

* update code-gen

* Add documentation and update manifests

* add e2e test and introduce option in configmap

* fix service annotations test

* Add unit test

* fix e2e tests

* better key lookup of annotations tests

* add debug message for annotation tests

* Fix typos

* minor fix for looping

* Handle update path and renaming

- handle the update path to update sts and connection pooler deployment.
  This way no need to wait for sync
- rename the parameter to downscaler_annotations
- handle other review comments

* another try to fix python loops

* Avoid unneccessary update events

* Update manifests

* some final polishing

* fix cluster_test after polishing

Co-authored-by: Rafia Sabih <rafia.sabih@zalando.de>
Co-authored-by: Felix Kunde <felix-kunde@gmx.de>

docs/reference/cluster_manifest.md

@@ -165,7 +165,7 @@ These parameters are grouped directly under  the `spec` key in the manifest.
   If `targetContainers` is empty, additional volumes will be mounted only in the `postgres` container.
   If you set the `all` special item, it will be mounted in all containers (postgres + sidecars).
   Else you can set the list of target containers in which the additional volumes will be mounted (eg : postgres, telegraf)
-  
+
 ## Postgres parameters
 
 Those parameters are grouped under the `postgresql` top-level key, which is

docs/reference/operator_parameters.md

@@ -200,6 +200,12 @@ configuration they are grouped under the `kubernetes` key.
   of a database created by the operator. If the annotation key is also provided
   by the database definition, the database definition value is used.
 
+* **downscaler_annotations**
+  An array of annotations that should be passed from Postgres CRD on to the
+  statefulset and, if exists, to the connection pooler deployment as well.
+  Regular expressions like `downscaler/*` etc. are also accepted. Can be used
+  with [kube-downscaler](https://github.com/hjacobs/kube-downscaler).
+
 * **watched_namespace**
   The operator watches for Postgres objects in the given namespace. If not
   specified, the value is taken from the operator namespace. A special `*`