Small issues with translatable strings

[webdados]

While helping with the translation of this plugin to Portuguese, on a translation contribution meetup last night, we found some issues that need to be fixed.

• The "NOTE: To enable the logging feature, you must define NGINX_HELPER_LOG constant as true in your wp-config.php" string for the "Enable Logging" option is confusing to translate, and it need to be refactored as a proper full sentence
• Some strings have a trailing space as they are concatenated with dynamic values, making them incompatible with languages where the phrase structure might be different. For example: esc_attr__( 'Posted ', 'nginx-helper' ) . esc_attr( $item->get_date( 'j F Y | g:i a' ) )