Cleanup configuration

Add pool configuration into CRD & charts. Add preliminary documentation.
Rename NumberOfInstances to Replicas like in Deployment. Mention couple
of potential improvement points for connection pool specification.

docs/reference/cluster_manifest.md

@@ -149,6 +149,11 @@ These parameters are grouped directly under  the `spec` key in the manifest.
   [the reference schedule format](https://kubernetes.io/docs/tasks/job/automated-tasks-with-cron-jobs/#schedule)
   into account. Optional. Default is: "30 00 \* \* \*"
 
+* enableConnectionPool
+  Tells the operator to create a connection pool with a database. If this
+  field is true, a connection pool deployment will be created even if
+  `connectionPool` section is empty.
+
 ## Postgres parameters
 
 Those parameters are grouped under the `postgresql` top-level key, which is
@@ -359,3 +364,25 @@ CPU and memory limits for the sidecar container.
 * **memory**
   memory limits for the sidecar container. Optional, overrides the
   `default_memory_limits` operator configuration parameter. Optional.
+
+## Connection pool
+
+Parameters are grouped under the `connectionPool` top-level key and specify
+configuration for connection pool. If this section is not empty, a connection
+pool will be created for a database even if `enableConnectionPool` is not
+present.
+
+* **replicas**
+  How many instances of connection pool to create.
+
+* **mode**
+  In which mode to run connection pool, transaction or section.
+
+* **schema**
+  Schema to create for credentials lookup function.
+
+* **user**
+  User to create for connection pool to be able to connect to a database.
+
+* **resources**
+  Resource configuration for connection pool deployment.

docs/reference/operator_parameters.md

@@ -592,3 +592,31 @@ scalyr sidecar. In the CRD-based configuration they are grouped under the
 
 * **scalyr_memory_limit**
   Memory limit value for the Scalyr sidecar. The default is `500Mi`.
+
+## Connection pool configuration
+
+Parameters are grouped under the `connection_pool` top-level key and specify
+default configuration for connection pool, if a postgres manifest requests it
+but do not specify some of the parameters. All of them are optional with the
+operator being able to provide some reasonable defaults.
+
+* **connection_pool_replicas**
+  How many instances of connection pool to create.
+
+* **connection_pool_schema**
+  Schema to create for credentials lookup function.
+
+* **connection_pool_user**
+  User to create for connection pool to be able to connect to a database.
+
+* **connection_pool_image**
+  Docker image to use for connection pool deployment.
+
+* **connection_pool_mode**
+  Default pool mode, sesssion or transaction.
+
+* **connection_pool_default_cpu_request**
+  **connection_pool_default_memory_reques**
+  **connection_pool_default_cpu_limit**
+  **connection_pool_default_memory_limit**
+  Default resource configuration for connection pool deployment.