Benchmark rework

[Gelbpunkt]

• No more deno, use a Python script
• Use Chimera Linux instead of Alpine Linux and LLVM everywhere instead of a random mix of GCC and LLVM
• Use https://musl.rs/ for nightly Rust sources that properly target LLVM and musl
• Reduce the time the benchmarks run for, this is best-effort anyways and more than >10 samples doesn't really change results
• Drop rust-websocket, that crate is horribly out of date and noone should be using it
• TODO: Re-run the benchmarks on my PC