Add Referrer field to AuditEntry

[ngoduykhanh]

Fix #3031

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[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (fb8a83d) 97.91% compared to head (27a2fa0) 97.91%.
Report is 1 commits behind head on master.

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #3032   +/-   ##
=======================================
  Coverage   97.91%   97.91%           
=======================================
  Files         150      150           
  Lines       12980    12980           
=======================================
  Hits        12710    12710           
  Misses        192      192           
  Partials       78       78           

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[gmlewis]

Thank you, @ngoduykhanh !
LGTM.
Merging.