[feat] Add support for dynamically setting the authorization header in the httpjson log handler

[JimPaine]

Enables the use of short lived tokens where http services use flows such as client credentials by allowing the authorization header to be set dynamically via a callable which is evaluated at the point the http request is made.

Closes #3622

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 91.64%. Comparing base (fc03052) to head (05bb049).
⚠️ Report is 7 commits behind head on develop.

Additional details and impacted files

@@             Coverage Diff             @@
##           develop    #3624      +/-   ##
===========================================
+ Coverage    91.37%   91.64%   +0.26%     
===========================================
  Files           62       62              
  Lines        13524    13530       +6     
===========================================
+ Hits         12358    12399      +41     
+ Misses        1166     1131      -35     

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[vkarak]

Lgtm, I have just minor style comments.

[vkarak]

Lgtm, thanks!