Add RTSP and minor fixes

[gpotter2]

• add RTSP
• minor tweaks to HTTP to support a wider range of HTTP-like protocols

[codecov[bot]]

Codecov Report

Merging #4279 (c1c2c30) into master (bb36cec) will increase coverage by 32.32%. Report is 2 commits behind head on master. The diff coverage is 81.17%.

Additional details and impacted files

@@             Coverage Diff             @@
##           master    #4279       +/-   ##
===========================================
+ Coverage   49.67%   81.99%   +32.32%     
===========================================
  Files         342      350        +8     
  Lines       76267    81909     +5642     
===========================================
+ Hits        37886    67165    +29279     
+ Misses      38381    14744    -23637     

Files	Coverage Δ
scapy/layers/msrpce/rpcclient.py	50.00% <100.00%> (+50.00%)	:arrow_up:
scapy/layers/http.py	81.08% <94.73%> (+56.01%)	:arrow_up:
scapy/layers/msrpce/msdcom.py	70.37% <14.28%> (+70.37%)	:arrow_up:
scapy/contrib/rtsp.py	84.21% <84.21%> (ø)

... and 262 files with indirect coverage changes