btrfs-progs: make btrfs qgroups show human readable sizes

btrfs-progs: make btrfs qgroups show human readable sizes

add --raw, --si, --iec, --kbytes, --mbytes, --gbytes, --tbytes options
make columns which show sizes align to right. Others aligned to left.

example:
qgroupid         rfer         excl     max_rfer     max_excl parent  child
--------         ----         ----     --------     -------- ------  -----
0/5         299.58MiB    299.58MiB    300.00MiB    300.00MiB 1/1     ---
0/265       299.58MiB     16.00KiB    400.00MiB        0.00B 1/1     ---
0/266       299.58MiB     16.00KiB    350.00MiB        0.00B ---     ---
1/1         599.16MiB    299.59MiB    800.00MiB        0.00B ---     0/5,0/265

Signed-off-by: Fan Chengniang <fancn.fnst@cn.fujitsu.com>
Signed-off-by: David Sterba <dsterba@suse.cz>