[Multi-Database Support] Optimize table case sensitivity

[shoothzj]

What's the purpose of this PR

I think if we want to support more databases, we should be more rigorous and pay closer attention to case sensitivity in more places.

Brief changelog

Quoted table name.

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[codecov]

Codecov Report

Merging #4768 (ce713ae) into master (e78712b) will not change coverage.
The diff coverage is n/a.

@@            Coverage Diff            @@
##             master    #4768   +/-   ##
=========================================
  Coverage     47.35%   47.35%           
  Complexity     1657     1657           
=========================================
  Files           346      346           
  Lines         10662    10662           
  Branches       1058     1058           
=========================================
  Hits           5049     5049           
  Misses         5307     5307           
  Partials        306      306           

Impacted Files	Coverage Δ
...m/ctrip/framework/apollo/biz/entity/AccessKey.java	58.33% <ø> (ø)
...a/com/ctrip/framework/apollo/biz/entity/Audit.java	52.94% <ø> (ø)
...com/ctrip/framework/apollo/biz/entity/Cluster.java	58.82% <ø> (ø)
.../com/ctrip/framework/apollo/biz/entity/Commit.java	5.55% <ø> (ø)
...p/framework/apollo/biz/entity/GrayReleaseRule.java	100.00% <ø> (ø)
...om/ctrip/framework/apollo/biz/entity/Instance.java	43.24% <ø> (ø)
...ip/framework/apollo/biz/entity/InstanceConfig.java	71.11% <ø> (ø)
...va/com/ctrip/framework/apollo/biz/entity/Item.java	86.36% <ø> (ø)
...m/ctrip/framework/apollo/biz/entity/Namespace.java	61.11% <ø> (ø)
...rip/framework/apollo/biz/entity/NamespaceLock.java	25.00% <ø> (ø)
... and 19 more

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[nobodyiam]

LGTM