Port V2G to Scapy

[polybassa]

This moves the layers from V2GInjector to Scapy Mainline.

@FlUxIuS are you OK with changing the license to GPLv2 only for this file?

AI-Assisted: yes (Cursor AI)

[codecov]

Codecov Report

❌ Patch coverage is 94.59459% with 2 lines in your changes missing coverage. Please review.
✅ Project coverage is 80.33%. Comparing base (fbd0956) to head (8d98051).

Files with missing lines	Patch %	Lines
scapy/contrib/automotive/v2g.py	94.59%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #5025      +/-   ##
==========================================
- Coverage   80.34%   80.33%   -0.01%     
==========================================
  Files         386      387       +1     
  Lines       96034    96071      +37     
==========================================
+ Hits        77154    77182      +28     
- Misses      18880    18889       +9     

Files with missing lines	Coverage Δ
scapy/contrib/automotive/v2g.py	94.59% <94.59%> (ø)

... and 4 files with indirect coverage changes

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