Postgres PVC Soak Fix

This patch fixes an issue with Postgres HA where
the PVC which stores the database was filling up with
WAL records and not deleting them due to some
misconfigurations with Postgres. Once the PVC
would fill up, replication would fail across the node
and the database would not be able to start, crashing
the system.

Specifically, archive_mode was turned on, but was not
supplied with a function through which to archive the
logs. When WAL archiving is turned on, old WAL files
cannot be removed until the system has archived them first.
However, since we never told the system how to archive the
files, it would repeatedly fail so the WAL files would
never be cleaned up.

Also in this patch are some small house keeping items:
- Lowered the wal_keep_segments drastically so Postgres
  can't keep as many WAL segments around to minimize the
  chance of PVC fill issues
- Turned the wal_level from 'logical' to 'hot_standby'
  to keep it consistent with the fact that Patroni uses
  streaming replication and not logical replication
- Removed the autovaccuum configurations as they are not
  needed

Change-Id: Id48c3ee9976823b2bdb4395a029fe75476bdaa62

postgresql/values.yaml

@@ -238,11 +238,7 @@ conf:
           pgpass: '{{ .Values.storage.mount.path }}/pgpass'
           use_pg_rewind: true
           parameters:
-            archive_mode: 'on'
-            archive_timeout: 1800s
-            autovacuum_analyze_scale_factor: 0.02
-            autovacuum_max_workers: 5
-            autovacuum_vacuum_scale_factor: 0.05
+            archive_mode: 'off'
             checkpoint_completion_target: 0.9
             datestyle: 'iso, mdy'
             default_text_search_config: 'pg_catalog.english'
@@ -271,8 +267,8 @@ conf:
             timezone: 'UTC'
             track_commit_timestamp: 'on'
             track_functions: all
-            wal_keep_segments: 100
-            wal_level: 'logical'
+            wal_keep_segments: 8
+            wal_level: hot_standby
             wal_log_hints: 'on'
       initdb:
       - auth-host: md5
@@ -300,11 +296,7 @@ conf:
         on_start: /tmp/set_password.sh
       use_pg_rewind: true
       parameters:
-        archive_mode: 'on'
-        archive_timeout: 1800s
-        autovacuum_analyze_scale_factor: 0.02
-        autovacuum_max_workers: 5
-        autovacuum_vacuum_scale_factor: 0.05
+        archive_mode: 'off'
         checkpoint_completion_target: 0.9
         datestyle: 'iso, mdy'
         default_text_search_config: 'pg_catalog.english'
@@ -333,9 +325,8 @@ conf:
         timezone: 'UTC'
         track_commit_timestamp: 'on'
         track_functions: all
-        shared_buffers: {{ .Values.conf.postgresql.shared_buffers }}
-        wal_keep_segments: 100
-        wal_level: 'logical'
+        wal_keep_segments: 8
+        wal_level: hot_standby
         wal_log_hints: 'on'
       pg_hba:
       - host all all 127.0.0.1/32 trust