refactor: storage, layout, and devices (mostly cartesian)

[romanc]

Description

PRs #1843 and #1867 raised a couple of questions regarding storage, layouts, and device support/handling on the cartesian side. This is a collector issue in which I'd like to group a couple small PRs and maybe have discussions around these refactors.

So far, we've identified a potential for improvement in the following areas:

• limit DeviceType to what is actually used/supported. PR refactor: stick to supported device types #1879
• share a centralized CUPY_DEVICE (currently defined separately in next and cartesian) in _core
• break the dependency cycle between storage and cartesian, see refactor[cartesian]: use DeviceType from core_defn in LayoutInfo #1867 (comment)
• get rid of GT4PY_USE_HIP environment variable since auto-detection of NVIDIA/AMD GPUs seems to work fine, see refactor[cartesian]: use DeviceType from core_defn in LayoutInfo #1867 (comment)
• [cartesian] Move Layout into Backend, see refactor[cartesian]: use DeviceType from core_defn in LayoutInfo #1867 (comment)

Consider this as a low-priority wish list for refactors on the side.