Win: HTTP_Client improvements

[gpotter2]

• better handling of http_client headers (now fully replaceable)
• support KKDCP over KerberosClient

[codecov]

Codecov Report

Attention: Patch coverage is 31.70732% with 28 lines in your changes missing coverage. Please review.

Project coverage is 81.60%. Comparing base (c2ce8dc) to head (bd1596c).
Report is 1 commits behind head on master.

Files with missing lines	Patch %	Lines
scapy/layers/kerberos.py	22.85%	27 Missing ⚠️
scapy/layers/http.py	83.33%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #4604      +/-   ##
==========================================
- Coverage   81.61%   81.60%   -0.01%     
==========================================
  Files         358      358              
  Lines       85678    85709      +31     
==========================================
+ Hits        69927    69946      +19     
- Misses      15751    15763      +12     

Files with missing lines	Coverage Δ
scapy/layers/http.py	82.71% <83.33%> (-0.23%)	⬇️
scapy/layers/kerberos.py	65.39% <22.85%> (-0.85%)	⬇️

... and 11 files with indirect coverage changes