usm_ndarray repr, str exposed in dpctl.tensor

[ndgrigorian]

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Exposed usm_ndarray_repr and usm_ndarray_str in dpctl.tensor.
This allows extensions and subclasses to leverage usm_ndarray_repr for printing with custom prefixes/class names, formatting, etc.
Unblocks IntelPython/dpnp#1279

[github-actions]

View rendered docs @ https://intelpython.github.io/dpctl/pulls/1060/index.html

[github-actions]

Array API standard conformance tests for dpctl=0.14.1dev1=py310h76be34b_60 ran successfully.
Passed: 33
Failed: 801
Skipped: 280

[github-actions]

Array API standard conformance tests for dpctl=0.14.1dev1=py310h76be34b_60 ran successfully.
Passed: 33
Failed: 801
Skipped: 280

[oleksandr-pavlyk]

Thank you @ndgrigorian ! This looks good. Please allow few hours to @vtavana to provide feedback.

[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=0.14.1dev1=py310h76be34b_75 ran successfully.
Passed: 33
Failed: 801
Skipped: 280