Added Czech translation.

interface/lib/lang/cz.lng

interface/web/admin/lib/lang/cz.lng

interface/web/admin/lib/lang/cz_firewall.lng

interface/web/admin/lib/lang/cz_firewall_list.lng

interface/web/admin/lib/lang/cz_groups.lng

interface/web/admin/lib/lang/cz_groups_list.lng

interface/web/admin/lib/lang/cz_language_add.lng

interface/web/admin/lib/lang/cz_language_complete.lng

interface/web/admin/lib/lang/cz_language_edit.lng

interface/web/admin/lib/lang/cz_language_export.lng

interface/web/admin/lib/lang/cz_language_import.lng

interface/web/admin/lib/lang/cz_language_list.lng

interface/web/admin/lib/lang/cz_remote_user.lng

interface/web/admin/lib/lang/cz_remote_user_list.lng

interface/web/admin/lib/lang/cz_server.lng

interface/web/admin/lib/lang/cz_server_config.lng

interface/web/admin/lib/lang/cz_server_config_list.lng

interface/web/admin/lib/lang/cz_server_ip.lng

interface/web/admin/lib/lang/cz_server_ip_list.lng

interface/web/admin/lib/lang/cz_server_list.lng