Small install feature issues

[adam-buckley]

Currently notice three issues from running a couple of installs recently:

1. The fields in the resulting config.php are all using double quotes, this is an issue when a password (or any text) has a special PHP char '$', '', etc.
2. When entering the database user credentials, on both occasions the next presented me with a "Database has no root user" warning message. Most of the time they actually do, but the user given doesn't have enough privileges to know, the message should perhaps be given as an info message.
3. The database migration install doesn't run any project module migrations... @careck should it?

[careck]

agreed to all points.