Add alternative implementation of device timer to SyclTimer class

[oleksandr-pavlyk]

This PR adds Python API to submit empty body single task to a queue. dpctl.SyclTimer is modified to acquire device_timer keyword argument with supported values being "queue_barrier" (legacy behavior, a default), and "order_manager".

With "order_manager", timer submits the empty body single tasks (fence tasks) to the queue, using order manager to order them so as to fence timed submissions. For example, execution of the following snippet:

   prior_ops
   with timer(profiling_queue):
        compute_using_the_queue
   subsequent_ops

results in a task graph [prior_tasks] -> [fence_start_task] -> [ compute_tasks] -> [fence_end_task] -> [subsequent_tasks].

Timer uses profiling data from events associated with fence tasks to estimate execution time of compute tasks as measured by the device's timer.

The device_timer="order_manager" is useful to time dpctl.tensor operations which leverage order manager.

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[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=0.19.0dev0=py310hdf72452_149 ran successfully.
Passed: 895
Failed: 0
Skipped: 119

[coveralls]

coverage: 87.725% (+0.02%) from 87.705%
when pulling 7752078 on add-empty-task-submission
into dd2812f on master.

[github-actions]

Array API standard conformance tests for dpctl=0.19.0dev0=py310hdf72452_150 ran successfully.
Passed: 894
Failed: 1
Skipped: 119

[github-actions]

Array API standard conformance tests for dpctl=0.19.0dev0=py310hdf72452_174 ran successfully.
Passed: 894
Failed: 1
Skipped: 119

[github-actions]

Array API standard conformance tests for dpctl=0.19.0dev0=py310hdf72452_177 ran successfully.
Passed: 894
Failed: 1
Skipped: 119

[github-actions]

Array API standard conformance tests for dpctl=0.19.0dev0=py310hdf72452_199 ran successfully.
Passed: 895
Failed: 0
Skipped: 119

[github-actions]

Array API standard conformance tests for dpctl=0.19.0dev0=py310hdf72452_209 ran successfully.
Passed: 894
Failed: 1
Skipped: 119

[github-actions]

Array API standard conformance tests for dpctl=0.19.0dev0=py310hdf72452_210 ran successfully.
Passed: 894
Failed: 1
Skipped: 119

[ndgrigorian]

LGTM!