Add max_failover_replication_time_lag configuration with constraints

- Set description for `max_failover_replication_time_lag`
- Define value constraints (min: 10, max: 9223372036854776000)
- Provide default (60) and example (4) values

specification/resources/databases/models/advanced_config/postgres_advanced_config.yml

@@ -407,3 +407,10 @@ properties:
       Enable the pg_stat_monitor extension. <b>Enabling this extension will cause the cluster to be restarted.</b> When this extension is enabled, pg_stat_statements results for utility commands are unreliable.
     type: boolean
     example: false
+  max_failover_replication_time_lag:
+    description: >-
+      Number of seconds of master unavailability before triggering database failover to standby.</b>  The default value is 60.
+    type: integer
+    minimum: 10
+    maximum: 9223372036854776000
+    example: 4