Add support for the XINFO command

[jxnu-liguobin]

#233
Refer to the design of jedis.It provide three method(sub command) as follows:

  void xinfoStream (String key);

  void xinfoGroup (String key);

  void xinfoConsumers (String key, String group);

Thefull option are not included.

Redis documents tell us that we can't rely on the number and order of returned fields, and we should record undefined fields. This is different from the implementation of jedis, in which all the original records are stored in a Map[String, Object].

Use undefined to record potentially unsupported fields.

[mijicd]

cc @anovakovic01

[anovakovic01]

Great job @jxnu-liguobin! With few changes, it will be ready for merge.

[jxnu-liguobin]

@anovakovic01 Please take a look

[anovakovic01]

LGTM!