Allow creating a SyclQueue from an exisiting SyclDevice (possibly sub-device) or SyclContext

[diptorupd]

Ability to create SyclQueue from instance of SyclDevice (and possibly SyclContext), which can be a sub-device.

Example:

import dpctl
with dpctl.on_device('gpu:1') as dev:
     X = dpnp.ones(10)  # kernels submitted to q associated with device `dev` and its default context

import dpctl
q = dpctl.SyclQueue(device="opencl:gpu:0")
dpctl.set_current_queue()

import dpctl
dev_parent = dpctl.SyclDevice("opencl:cpu:0")
subdevices = dev.parent.create_sub_devices([6, 6])
dpctl.set_current_queue(dpctl.SyclQeueue( subdevices[0]))

[diptorupd]

Implemented and will be part of 0.7.0.