*: introduce QueryRegion stream

[JmPotato]

What problem does this PR solve?

Issue Number: ref #8690.

What is changed and how does it work?

Check List

Tests

• Unit test
• Integration test
• Manual test (add detailed scripts or steps below)
• No code

Code changes

• Has the configuration change
• Has HTTP API interfaces changed (Don't forget to add the declarative for the new API)
• Has persistent data change

Side effects

• Possible performance regression
• Increased code complexity
• Breaking backward compatibility

Related changes

• PR to update pingcap/docs/pingcap/docs-cn:
• PR to update pingcap/tiup:
• Need to cherry-pick to the release branch

Release note

None.

[ti-chi-bot]

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[ti-chi-bot]

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[codecov]

Codecov Report

Attention: Patch coverage is 53.76344% with 43 lines in your changes missing coverage. Please review.

Project coverage is 75.65%. Comparing base (20087e2) to head (568bd46).
Report is 11 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #8708      +/-   ##
==========================================
+ Coverage   75.61%   75.65%   +0.04%     
==========================================
  Files         460      460              
  Lines       72135    72225      +90     
==========================================
+ Hits        54543    54645     +102     
+ Misses      14104    14100       -4     
+ Partials     3488     3480       -8     

Flag	Coverage Δ
unittests	75.65% <53.76%> (+0.04%)	⬆️

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[ti-chi-bot]

PR needs rebase.

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