quota: Implement quota format with 64-bit space and inode limits

So far the maximum quota space limit was 4TB. Apparently this isn't enough
for Lustre guys anymore. So implement new quota format which raises block
limits to 2^64 bytes. Also store number of inodes and inode limits in
64-bit variables as 2^32 files isn't that insanely high anymore.

The first version of the patch has been developed by Andrew Perepechko
<Andrew.Perepechko@Sun.COM>.

CC: Andrew.Perepechko@Sun.COM
Signed-off-by: Jan Kara <jack@suse.cz>