Give conf writes a backup, a lock and a read-back before they count

These files are gitignored, so a bad write had nothing to go back to; the escaping order
also stored any value containing a quote truncated but still parseable, which only a
read-back can catch.

Plugin/unraid/include/config.php

@@ -117,6 +117,8 @@ define('STATE_DIR',        DATA_DIR . '/state');
 define('AI_DATA_DIR',      DATA_DIR . '/ai');
 define('CACHE_BACKUP_DIR', DATA_DIR . '/cache');
 define('LOG_ARCHIVE_DIR',  DATA_DIR . '/logs');
+define('BACKUP_DIR',       DATA_DIR . '/Backups');
+define('CONF_BACKUP_DIR',  BACKUP_DIR . '/Confs');
 define('LOG_DIR',     '/var/log/varaverk');
 // User-authored custom scripts (scheduler page "+ Create Script") — kept outside the git
 // repo entirely, alongside the User Scripts plugin's own storage. Any *.sh file placed