fix(code/discovery): connection upgrades and multiaddr issues

[bastienfaivre]

Closes: #1056

---

PR author checklist

For all contributors

• Reference a GitHub issue
• Ensure the PR title follows the conventional commits spec
• Add a release note in RELEASE_NOTES.md if the change warrants it
• Add an entry in BREAKING_CHANGES.md if the change warrants it

For external contributors

• Maintainers of Malachite are allowed to push changes to the branch

[codecov]

Codecov Report

Attention: Patch coverage is 76.50273% with 86 lines in your changes missing coverage. Please review.

Project coverage is 76.95%. Comparing base (82186b9) to head (a893a29).

✅ All tests successful. No failed tests found.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1060      +/-   ##
==========================================
+ Coverage   76.31%   76.95%   +0.64%     
==========================================
  Files         159      159              
  Lines       16512    16588      +76     
  Branches    16512    16588      +76     
==========================================
+ Hits        12600    12764     +164     
+ Misses       3101     2998     -103     
- Partials      811      826      +15     

Flag	Coverage Δ
integration	76.74% <76.50%> (+0.63%)	⬆️
mbt	8.03% <0.00%> (-0.04%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Components	Coverage Δ
core	85.45% <ø> (ø)
engine	74.59% <ø> (-0.08%)	⬇️
app	86.32% <ø> (ø)
starknet	73.25% <100.00%> (-0.06%)	⬇️

[bastienfaivre]

Discovery now supports all the listening addresses of a node, especially when listening on 0.0.0.0. Moreover, the connection upgrade issue has been fixed by changing the connection philosophy: we now follow the same principle as in libp2p, where there can be multiple connections to a single peer. Therefore, the number of connections is now counted at the peer level, not the connection level. This introduces a new parameter max_connections_per_peer in the discovery config.