Refactored kernel dispatch API.

  - The concept of a kernel was decoupled from the notion of
    dispatching of a kernel. The present implementation in
    compiler.py intermixes both things, making hard the
    separation of compute-follows-data based kernel launch
    and legacy `dpctl.device_context` based behavior.
  - Deprecates support for numpy arrays as kernel args.
  - Deprecates support for the square bracket notation using
    `__getitem__` to provide global and local ranges for a
    kernel launch.
  - Changes the behavior of specializing a kernel using only
    a signature. The new way to specialize will require a
    device type and a backend.
  - Improvements to exception messages using custom exceptions.
  - The new API is now inside `numba_dpex.core.kernel_interface`.

Author: Diptorup Deb

numba_dpex/core/kernel_interface/__init__.py

@@ -0,0 +1,6 @@
+# SPDX-FileCopyrightText: 2020 - 2022 Intel Corporation
+#
+# SPDX-License-Identifier: Apache-2.0
+
+"""Defines the Kernel classes that abstract a SYCL device kernel.
+"""