Add message statistics and speedtest messages

[egbertbouman]

This PR does the following:

• Adds message statistics for all IPv8 + tunnel traffic.
• Drops messages with unknown prefixes. Until now, these were handed over to IPv8.
• Fix an issue with the socket not closing correctly when calling Endpoint.close.
• Updates all Rust dependencies to their most recent version.
• Updates GitHub workflows and adds support for Python 3.13.
• Adds test-request/response handlers. These were still being handled by Python, which made them unsuitable for measuring circuit throughput. The way we measure throughput has also changed, and we now slow down sending when a target RTT is surpassed.