Retrieve information from each site's database and present in grid

For example, present a grid of sites/active modules so one can easily see which module is in use on which site at a glance.

I have actually done this and will post a patch shortly.

This method includes running a separate PHP job to execute each sites settings.php script and return the DB Url. This is preferable to trying to parse each file as it may do 'funny' things (I know I do in my multi-site code).

Once each site's database URL is know, one can connect and retrieve any number of useful pieces of information. I started by returning a list of active modules and presenting in a grid, but this could be expanded in many ways (see #918206 for example).