Provide liveness probe for CRD and config (#3089)

* add LivenessProbe to both CRDs 
* auto-generate liveness probe for CRD
* update topolgySpreadConstraint schema validation
* Disable it for config map

docs/reference/cluster_manifest.md

@@ -85,6 +85,10 @@ These parameters are grouped directly under  the `spec` key in the manifest.
   requires a custom Spilo image. Note the FSGroup of a Pod cannot be changed
   without recreating a new Pod. Optional.
 
+* **livenessProbe**
+  Allows for adding a liveness probe to the Spilo container to detect if it's
+  running properly.
+
 * **enableMasterLoadBalancer**
   boolean flag to override the operator defaults (set by the
   `enable_master_load_balancer` parameter) to define whether to enable the load

docs/reference/operator_parameters.md

@@ -334,6 +334,10 @@ configuration they are grouped under the `kubernetes` key.
   Postgres pods are [terminated forcefully](https://kubernetes.io/docs/concepts/workloads/pods/pod-lifecycle/#pod-termination)
   after this timeout. The default is `5m`.
 
+* **liveness_probe**
+  Allows for adding a liveness probe to the Spilo container to detect if it's
+  running properly. Cannot be configured via ConfigMap. Default is empty.
+
 * **custom_pod_annotations**
   This key/value map provides a list of annotations that get attached to each pod
   of a database created by the operator. If the annotation key is also provided