Supporting non-NVIDIA GPUs

[mdw771]

Features/fixes

Created a wrapper for device-related operations that used to be CUDA-specific. This includes:

• torch.cuda
• tensor.cuda()

To run with Intel GPUs, users should add the following to the run script:

torch.set_default_device("xpu")
ptychi.device.set_torch_accelerator_module(torch.xpu)

Checklist

Have you...

• Formatted your code properly adhering to PEP-8? Considering using RUFF to format your code automatically.
• Resolved all merge conflicts with the main branch?
• Checked the diffs between your branch and the main branch to ensure that your changes are not introducing any regressions or unnecessary/irrelevant changes?