Add count cmd including quota usage

[meoww-bot]

Thanks for your code , it's perfect that native support kerberos without any other 3rd-party dependence.

I want to add quota-related support to this gohdfs client.

So firstly I try to add count -q.

root@datanode:/# time /tmp/hdfs count -q -h /user/hive
QUOTA   REM_QUOTA SPACE_QUOTA REM_SPACE_QUOTA DIR_COUNT FILE_COUNT CONTENT_SIZE PATHNAME
none    inf       1.0G        1.0G            4         0          0B           /user/hive

real	0m0.014s
user	0m0.010s
sys	0m0.004s
root@datanode:/# time /opt/hadoop-3.2.1/bin/hdfs dfs -count -h -q -v /user/hive
       QUOTA       REM_QUOTA     SPACE_QUOTA REM_SPACE_QUOTA    DIR_COUNT   FILE_COUNT       CONTENT_SIZE PATHNAME
        none             inf             1 G             1 G            4            0                  0 /user/hive

real	0m2.281s
user	0m3.138s
sys	0m0.689s