[FEA]: Support fancy iterators in cuda.parallel

### Is this a duplicate?

- [x] I confirmed there appear to be no [duplicate issues](https://github.com/NVIDIA/cccl/issues) for this request and that I agree to the [Code of Conduct](CODE_OF_CONDUCT.md)

### Area

General CCCL

### Is your feature request related to a problem? Please describe.

Compared to existing solutions in PyTorch and CuPy, one of the distinguishing features of cuda.parallel is flexibility. Part of that flexibility is coming from support of user-defined data types and operators. But compared to CUDA C++ solution, cuda.parallel API is still limited. We are still missing fancy iterators and cache modified iterators in cuda.parallel.

### Describe the solution you'd like

Given that fancy iterators support might require rather invasive changes to cuda.parallel and CCCL/c libraries, we should design fancy iterators before introducing more algorithms to cuda.parallel.

### Describe alternatives you've considered

_No response_

### Additional context

_No response_