Added remote functions config_value_get, config_value_add, config_value_update, config_value_replace and config_value_delete to access the sys_config key / value store in ISPConfig from remote api.

Add description text for logging options.

global option to enable pagespeed with nginx - allows to enable pagespeed even if no webserver-config is selected

- fixed escaping in lists

Added a server migration mode setting which will be used to prevent that LE tries to recreate certs during a server migration.