[FEA] Support for Graph APIs

[gmarkall]

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

A graph API proposal was made at numba/numba#4182

I've backed up the branch from the original PR in case it becomes unavailable in future, at https://github.com/gmarkall/numba/tree/cuda-graph-proposal

Describe the solution you'd like

Numba-cuda should use the design / implementation that is planned for CUDA Python, tracked in NVIDIA/cuda-python#111

Describe alternatives you've considered

The existing PR provides a new API within Numba - whilst it's possible to run ahead in Numba-CUDA and implement our own API, for the long term it would be better to align with CUDA Python and avoid a duplication of effort and / or divergent implementation.

Additional context

None.