Implemented passwordless ssh-rsa authentication support.

install/sql/incremental/upd_0008.sql

+-- database patch for rsa-key based shell access.
+ALTER TABLE `sys_user` ADD `id_rsa` VARCHAR( 2000 ) NOT NULL ;
+ALTER TABLE `sys_user` ADD `ssh_rsa` VARCHAR( 600 ) NOT NULL ;
+ALTER TABLE `shell_user` ADD `ssh_rsa` VARCHAR( 600 ) NOT NULL ;