Host task cleanup

[ndgrigorian]

Draft pull request for collecting host_tasks throughout dpctl to prevent dangling tasks, which are suspected to cause crashes.
May be related to #1063

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• Have you made sure that new changes do not introduce compiler warnings?
• If this PR is a work in progress, are you filing the PR as a draft?

[github-actions]

View rendered docs @ https://intelpython.github.io/dpctl/pulls/1111/index.html

[coveralls]

Coverage: 82.404%. Remained the same when pulling fd9286c on host-task-cleanup into cecfdaa on master.

[github-actions]

Array API standard conformance tests for dpctl=0.14.2=py310h76be34b_13 ran successfully.
Passed: 46
Failed: 788
Skipped: 280

[oleksandr-pavlyk]

Thank you @ndgrigorian

[github-actions]

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

[github-actions]

Array API standard conformance tests for dpctl=0.14.2=py310h76be34b_35 ran successfully.
Passed: 46
Failed: 788
Skipped: 280