Add layer HICP

[claire-lex]

Checklist:

• If you are new to Scapy: I have checked CONTRIBUTING.md (esp. section submitting-pull-requests)
• I squashed commits belonging together
• I added unit tests or explained why they are not relevant
• I executed the regression tests (using cd test && ./run_tests or tox)
• If the PR is still not finished, please create a Draft Pull Request

This PR adds support for a new protocol in contrib: HICP
The protocol is used by industrial devices HMS Anybus for network discovery and configuration.
All the messages used by the official HMS IPconfig software are implemented.

[codecov]

Codecov Report

Merging #4075 (f6dd968) into master (7d31fcc) will increase coverage by 0.02%.
The diff coverage is 89.86%.

@@            Coverage Diff             @@
##           master    #4075      +/-   ##
==========================================
+ Coverage   81.95%   81.98%   +0.02%     
==========================================
  Files         327      328       +1     
  Lines       75568    75766     +198     
==========================================
+ Hits        61935    62113     +178     
- Misses      13633    13653      +20     

Files Changed	Coverage Δ
scapy/contrib/hicp.py	89.86% <89.86%> (ø)

... and 19 files with indirect coverage changes

[gpotter2]

Thanks for the PR ! It looks solid.

Minor nit found by the CI.

Scapy's support for text-based protocols is subpar, so congrats on making that work !