Feature: QuantizeOperator

Similar to `buffer_when`, with some extra options, as the "closing_observable" that causes the buffer to be forwarded must emit `Cadence` signals.
- Another option is to select the beat it should quantize to, which too should be observable.
- Option to always emit up to a beat level, or even firehosing, regardless of observed upstream events. This too could be an observable.
- outputs are also not just re-emits of the input value like with `buffer_when`, but wrapped with extra data about when it was actually buffered (`now` timestamp)

### Additional Information

- "Holding" of quantized events for a specific duration is the job of another operator, this operator should strictly work with discrete events in time, and should not concern itself with the concept of "duration" or "length"

- Consider: Dampening, from a marked upstream event that can ignore quantization, but return to it after a time, with an easing function.

### User Recommendations

- User input directly should not be quantized, as that would delay any possible reaction to the users input. Only second order events should be quantized!