Add fuzzing targets

[tomaka]

This PR adds fuzzing binaries to the smoldot repo.
I've added one for every fuzzable thing that I could think of.

I've only let them run maybe 15 minutes each, so there's room for running things over night to detect crashes.

Many of them are failing because of #2340

The network-connection-encrypted fuzzing test is failing a lot, but that's good, and I'll have to fix all the issues that arise.

[mergify]

Automatically approving tomaka's pull requests. This auto-approval will be removed once more maintainers are active.

[github-actions]

twiggy diff report

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[melekes]

🚀 🌔