`AudioWorklet` improvements

[b-ma]

Remaining todos and ideas following #124

• [x] Review rules and fix number of channels outputs when input change
• [x] Use a pool of Float32Array channels to avoid allocation and GC (as much as possible)
• [ ] Ensure we run run_audio_worklet_global_scope and setImmediate only once per render quantum
• [ ] Use the fact that parameterDescriptors are ordered to avoid transferring parameter keys, i.e. NapiAudioWorlketProcessor::param_values could just be Vec<&'static [f32]>
• [ ] Review how message passing is done between audio and worklet threads (possibly use parking_lot crate ?)
• [ ] ~Dry run process functions to force the JIT compiler to optimize them ? (might break some wpt checks)~ could create issues If the worklet buffer some values
• [ ] Review and annotate unsafe sections
• [ ] Change the thread_priority crate to https://github.com/mozilla/audio_thread_priority
• [ ] Use a CondVar instead of crossbeam channel for Worker/Rust message passing
• [ ] Propagate back error to rust thread in case of WorkletAbruptCompletionResult to remove the Worklet from graph
• [ ] ...