Removed post-link and pre-unlink scripts

[oleksandr-pavlyk]

They provided a crutch, which is now handled by
intel-gpu-ocl-icd-system conda package, which a user may install as needed.

Since MKL currently requires OpenCL GPU device to be available, dpnp has run-time dependency on
intel-gpu-ocl-icd-system to make OpenCL GPU device discoverable by OpenCL loader from Python environment.

• Have you provided a meaningful PR description?
• Have you added a test, reproducer or referred to an issue with a reproducer?
• Have you tested your changes locally for CPU and GPU devices?
• Have you made sure that new changes do not introduce compiler warnings?
• Have you checked performance impact of proposed changes?
• If this PR is a work in progress, are you opening the PR as a draft?

[github-actions]

Deleted rendered PR docs from intelpython.github.com/dpctl, latest should be updated shortly. 🤞

[oleksandr-pavlyk]

The scripts being removed here were added in 7dc575a

[github-actions]

Array API standard conformance tests for dpctl=0.18.0dev0=py310hdf72452_395 ran successfully.
Passed: 895
Failed: 0
Skipped: 119

[coveralls]

coverage: 87.893%. remained the same
when pulling b767dcb on remove-post-link-and-pre-unlink-scripts
into aad69b0 on master.