sycl::vec overloads for elementwise functions

[ndgrigorian]

This PR adds overloads for sycl::vec input to the implementations of dpctl.tensor.abs, dpctl.tensor.cos, dpctl.tensor.expm1, dpctl.tensor.log, dpctl.tensor.log1p, and dpctl.tensor.sqrt.

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• Have you checked performance impact of proposed changes?
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[github-actions]

View rendered docs @ https://intelpython.github.io/dpctl/pulls/1223/index.html

[coveralls]

coverage: 85.942%. remained the same
when pulling 67bde59 on elementwise-func-fixes
into 5ec9fd5 on master.

[github-actions]

Array API standard conformance tests for dpctl=0.14.3dev3=py310h7bf5fec_9 ran successfully.
Passed: 259
Failed: 741
Skipped: 116

[oleksandr-pavlyk]

@ndgrigorian Please check that enabling vec brings on performance benefits on Max GPU.

[github-actions]

Array API standard conformance tests for dpctl=0.14.3dev3=py310h7bf5fec_20 ran successfully.
Passed: 320
Failed: 680
Skipped: 119

[github-actions]

Array API standard conformance tests for dpctl=0.14.4=py310h7bf5fec_11 ran successfully.
Passed: 388
Failed: 612
Skipped: 119

[github-actions]

Array API standard conformance tests for dpctl=0.14.5dev1=py310h7bf5fec_10 ran successfully.
Passed: 448
Failed: 552
Skipped: 119

[github-actions]

Array API standard conformance tests for dpctl=0.14.6dev0=py310h7bf5fec_6 ran successfully.
Passed: 474
Failed: 526
Skipped: 119

[github-actions]

Array API standard conformance tests for dpctl=0.15.1dev2=py310h15de555_20 ran successfully.
Passed: 876
Failed: 55
Skipped: 59

[ndgrigorian]

Testing has been performed and little-to-no significant performance gains were found for unary functions using sycl::vec overloads.

TODO: benchmark with sub-group loading disabled as well.