api: supports requests can redirect from leader to follower

[nolouch]

What problem does this PR solve?

Issue Number: Close #6904

What is changed and how does it work?

Reduce the leader pressure by proxy requests to followers
- supports requests can redirect from leader to follower 

Check List

Tests

• Unit test

Release note

None.

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[codecov]

Codecov Report

Merging #6905 (82a4c02) into master (ebd2cfe) will increase coverage by 0.00%.
Report is 63 commits behind head on master.
The diff coverage is 88.17%.

@@           Coverage Diff           @@
##           master    #6905   +/-   ##
=======================================
  Coverage   74.21%   74.22%           
=======================================
  Files         427      427           
  Lines       45127    45172   +45     
=======================================
+ Hits        33491    33528   +37     
+ Misses       8685     8683    -2     
- Partials     2951     2961   +10     

Flag	Coverage Δ
unittests	74.22% <88.17%> (+<0.01%)	⬆️

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[ti-chi-bot]

PR needs rebase.

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