Optionally create standard indices when formatting BFS

[humdinger]

This is hrev54905.

Newly BFS-formatted partitions don't have extended attributes indexed. So, if you plan to use that partition for data like mail, images, music, etc. queries on those attributes won't work, even though you have checked the mark "Enable query support" in DriveSetup when formatting the partition.

Should we have DriveSetup create those indices (basically a 'mkindex --copy-from /boot') when formatting BFS with query support? I guess there could be a second checkmark "Create indices" in that dialog, but I think it's a bit too technical...

I assume if some of those indices are unused in the end (maybe you won't store emails on the partition), the performace penalty is negligible?