btrfs-progs: right-align number columns in btrfs-debugfs output

btrfs-progs: right-align number columns in btrfs-debugfs output

The values for block group offset, length etc. in btrfs-debugfs' output
are left-aligned, which creates unaligned output and makes the usage
percentage hard to read/process further. This patch adds right-aligning
format specifiers for the number values.
Ideally the format values wouldn't be hardcoded but instead derived from
the filesystem size, but this seems to work for now.

Signed-off-by: Holger Hoffstätte <holger@applied-asynchrony.com>
Signed-off-by: David Sterba <dsterba@suse.com>