[Feature] Add FeedbackBlockCustom.

[Yshuo-Li]

Based on #345

[codecov]

Codecov Report

❗ No coverage uploaded for pull request base (fb@c3ddfdc). Click here to learn what that means.
The diff coverage is n/a.

@@          Coverage Diff          @@
##             fb     #348   +/-   ##
=====================================
  Coverage      ?   80.25%           
=====================================
  Files         ?      182           
  Lines         ?     9564           
  Branches      ?     1394           
=====================================
  Hits          ?     7676           
  Misses        ?     1698           
  Partials      ?      190           

Flag	Coverage Δ
unittests	80.23% <0.00%> (?)

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[innerlee]

@Yshuo-Li Sorry forgot to change the target branch to master :( pls make a pr again