Put secrets in another file.

This commit makes it easier to make changes to the instance config
without worrying about overwriting secrets and database configuration.

It also mitigates some possibility of leaking secrets.

inc/instance-config.secret.php.EXAMPLE

@@ -0,0 +1,24 @@
+<?php
+
+/*
+*  Instance Configuration Secrets
+*  ------------------------------
+*  Put secrets here to avoid accidentally leaking them in commits.
+*
+*/
+
+/*
+ * Database configuration
+ */
+
+$config['db']['server'] = 'localhost';
+$config['db']['database'] = 'lainchan';
+$config['db']['prefix'] = '';
+$config['db']['user'] = 'lainchan';
+$config['db']['password'] = '';
+
+/*
+ * Salt
+ */
+$config['secure_trip_salt'] = '';
+$config['cookies']['salt'] = '';