Implement QOL properties of usm_ndarray

[oleksandr-pavlyk]

This PR implements request for quality-of-life properties of usm_ndarray requested in gh-1192. It adds usm_ndarray._element_offset and usm_ndarray._byte_bounds.

The _element_offset gives the offset of the start of array from the beginning of the start of allocation in elements.

_byte_bounds gives the tuple with addresses of end-points of the array. Not every memory element in between the end-points may be addressed by indexing.

In [1]: import dpctl.tensor as dpt

In [2]: dpt.empty(10)[5:]._element_offset
Out[2]: 5

In [3]: dpt.empty(10)[5:]._byte_bounds
Out[3]: (18446664917462351892, 18446664917462351912)

In [4]: _[1] - _[0]
Out[4]: 20

In [5]: dpt.empty(10)[5:].itemsize
Out[5]: 4

Tests are added. This PR resolves gh-1192

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[coveralls]

Coverage: 83.299% (+0.04%) from 83.259% when pulling 4eb94f4 on qol-usm-ndarray-changes into 2da47aa on master.

[github-actions]

View rendered docs @ https://intelpython.github.io/dpctl/pulls/1199/index.html

[github-actions]

Array API standard conformance tests for dpctl=0.14.3dev1=py310h76be34b_40 ran successfully.
Passed: 153
Failed: 847
Skipped: 116

[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=0.14.3dev1=py310h76be34b_44 ran successfully.
Passed: 153
Failed: 847
Skipped: 116