Redis支持显示表列表

[feiazifeiazi]

Redis支持显示表列表：
什么是表？Redis的一个个Key就是一个个表。(只显示100个)

示例效果：

[codecov]

Codecov Report

Attention: Patch coverage is 96.66667% with 1 line in your changes missing coverage. Please review.

Project coverage is 78.40%. Comparing base (69e29b1) to head (7a126bc).
Report is 1 commits behind head on master.

Files with missing lines	Patch %	Lines
sql/engines/redis.py	93.75%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #2888      +/-   ##
==========================================
+ Coverage   78.37%   78.40%   +0.03%     
==========================================
  Files         124      124              
  Lines       17598    17628      +30     
==========================================
+ Hits        13793    13822      +29     
- Misses       3805     3806       +1     

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[feiazifeiazi]

@LeoQuote 新年好。 这个PR给看看呢？能否合？