A file is now always "ready" in the sense that is always has a type

The file is initially determined as a best guess
This also remove images from supported extensions

This reverts commit 5ac40117.
There was no lock involved, I blame E_NOCOFEE :|

It's now true when all metadata services have been run. The type is
still exposed and can be used to figure out if the basic metadata are
available

This will be meant for potential future callbacks, in order to avoid
passing multiple one method callbacks to IMediaLibrary::initialize()

Instead, automatically add available service.

Let the media library parse any new file it finds