add log (#492)

|       env              | image_env               | default_value          |
|---------------------|----------------------|-------------|
| logging_collector   | LOGGING_COLLECTOR    | off         |
| log_directory       | LOG_DIRECTORY        | pg_log      |
| log_filename        | LOG_FILENAME         | xxx         |
| log_rotation_age    | LOG_ROTATION_AGE     | 1d          |
| log_rotation_size   | LOG_ROTATION_SIZE    | 100MB       |
| log_truncate_on_rotation | LOG_TRUNCATE_ON_ROTATION | on         |
| log_lock_waits      | LOG_LOCK_WAITS       | on          |
| log_duration        | LOG_DURATION         | on          |
| log_statement       | LOG_STATEMENT        | all         |
| log_min_duration_statement | LOG_MIN_DURATION_STATEMENT | 20        |
| log_connections     | LOG_CONNECTIONS      | on          |
| log_disconnections  | LOG_DISCONNECTS      | on          |
| log_line_prefix     | LOG_LINE_PREFIX      | xx          |
| log_timezone        | LOG_TIMEZONE         | Etc/UTC     |