Add json_extract plugin

[kirillov6]

Description

Added json_extract action plugin.

Fixes #589

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 81.81818% with 12 lines in your changes are missing coverage. Please review.

Project coverage is 70.88%. Comparing base (6de60c8) to head (26dc115). Report is 1 commits behind head on master.

:exclamation: Current head 26dc115 differs from pull request most recent head eccda27. Consider uploading reports for the commit eccda27 to get more accurate results

Files	Patch %	Lines
plugin/action/json_extract/json_extract.go	81.81%	7 Missing and 5 partials :warning:

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #590      +/-   ##
==========================================
- Coverage   70.91%   70.88%   -0.04%     
==========================================
  Files         123      120       -3     
  Lines       12496    12406      -90     
==========================================
- Hits         8862     8794      -68     
+ Misses       3117     3094      -23     
- Partials      517      518       +1     

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