feat: add miscellaneous CUDA kernels

[ManasviGoyal]

Added following CUDA kernels:

• awkward_IndexedArray_flatten_none2empty
• awkward_ListArray_combinations_length
• awkward_ListOffsetArray_local_preparenext
• awkward_sorting_ranges
• awkward_ListArray_rpad_axis1 (variable-length inner loop)
• awkward_ListOffsetArray_rpad_axis1
• awkward_NumpyArray_pad_zero_to_length

[ManasviGoyal]

@jpivarski Packaging tests for ubuntu seem to be failing for all PRs

[jpivarski]

It's not finding numpy.AxisError, and it looks like it's installing numpy-1.26.4, not NumPy 2.0 or anything. That's very strange. Maybe it's installing a different NumPy at a later stage in the workflow? (I didn't follow it through to the end.)

[ManasviGoyal]

It's not finding numpy.AxisError, and it looks like it's installing numpy-1.26.4, not NumPy 2.0 or anything. That's very strange. Maybe it's installing a different NumPy at a later stage in the workflow? (I didn't follow it through to the end.)

I do see NumPy 2.0 before the error

Successfully installed awkward-cpp-30 numpy-2.0.0b1

[jpivarski]

Then #2936 has arrived, @tcawlfield!

[jpivarski]

Looks great! I thought I had reviewed and merged this earlier, but apparently hadn't. I had no comments or changes then, so I'll merge it now.