feat: implement virtual arrays

[ikrommyd]

This is a PR that aims to implement virtual buffers that are materialized when their actual data is needed. Getting those data would typically be an expensive disk read.
The description shall be updated in the future and become a lot more analytical.

[codecov]

Codecov Report

Attention: Patch coverage is 57.96703% with 153 lines in your changes missing coverage. Please review.

Project coverage is 81.98%. Comparing base (b749e49) to head (536a0d2).
Report is 265 commits behind head on main.

Files with missing lines	Patch %	Lines
src/awkward/_nplikes/virtual.py	39.72%	88 Missing ⚠️
src/awkward/operations/ak_materialize.py	44.00%	14 Missing ⚠️
src/awkward/_nplikes/array_module.py	80.32%	12 Missing ⚠️
src/awkward/_nplikes/cupy.py	9.09%	10 Missing ⚠️
src/awkward/contents/bitmaskedarray.py	25.00%	6 Missing ⚠️
src/awkward/_backends/dispatch.py	37.50%	5 Missing ⚠️
src/awkward/_nplikes/dispatch.py	37.50%	5 Missing ⚠️
src/awkward/prettyprint.py	57.14%	3 Missing ⚠️
src/awkward/contents/unionarray.py	86.66%	2 Missing ⚠️
src/awkward/_kernels.py	66.66%	1 Missing ⚠️
... and 7 more

Additional details and impacted files

Files with missing lines	Coverage Δ
src/awkward/_nplikes/__init__.py	82.60% <100.00%> (+0.79%)	⬆️
src/awkward/_nplikes/numpy.py	92.30% <100.00%> (+0.20%)	⬆️
src/awkward/_nplikes/numpy_like.py	99.02% <100.00%> (+23.73%)	⬆️
src/awkward/contents/emptyarray.py	75.70% <100.00%> (+0.07%)	⬆️
src/awkward/contents/listarray.py	90.34% <100.00%> (+0.90%)	⬆️
src/awkward/contents/listoffsetarray.py	80.89% <100.00%> (-1.97%)	⬇️
src/awkward/contents/numpyarray.py	90.77% <100.00%> (-0.74%)	⬇️
src/awkward/contents/recordarray.py	84.54% <100.00%> (-0.66%)	⬇️
src/awkward/contents/regulararray.py	86.28% <100.00%> (-1.11%)	⬇️
src/awkward/operations/__init__.py	100.00% <100.00%> (ø)
... and 17 more

... and 154 files with indirect coverage changes