Functions to persist authentication state to a RDMS via knex

DDL

	CREATE TABLE `user` (
	`pk` int(10) unsigned NOT NULL AUTO_INCREMENT,
	`username` varchar(50) NOT NULL,
	`password` varchar(255) NOT NULL,
	`password_secondary` varchar(255) DEFAULT NULL,
	`password_expiry_date` datetime DEFAULT NULL,
	`login_expiry_date` datetime DEFAULT NULL,
	`created_time` datetime DEFAULT NULL,
	`deactivate` varchar(3) NOT NULL DEFAULT 'no',
	`password_new` varchar(64) DEFAULT NULL,
	`last_login` datetime DEFAULT NULL,
	`type` enum('HUMAN','SYSTEM') NOT NULL DEFAULT 'HUMAN',
	`login_failed_count` int(10) unsigned DEFAULT 0,
	`last_login_failed` datetime DEFAULT NULL,
	PRIMARY KEY (`pk`),
	UNIQUE KEY `unique_1` (`username`)
	) ENGINE=InnoDB DEFAULT CHARSET=utf8