[SYCL][PI][L0] Add blitter engine support in level zero plugin (#3369)

Level Zero plugin submits all operation to level zero compute queues and both compute and memory operations are submitted to be executed on the compute engine. This change submits some of the memory operations to a level zero copy queue and such operations will be executed on the copy engine.

Author: asudarsa

sycl/doc/EnvironmentVariables.md

@@ -30,6 +30,7 @@ subject to change. Do not rely on these variables in production code.
 | SYCL_PI_LEVEL_ZERO_DISABLE_USM_ALLOCATOR | Any(\*) | Disable USM allocator in Level Zero plugin (each memory request will go directly to Level Zero runtime) |
 | SYCL_PI_LEVEL_ZERO_BATCH_SIZE | Integer | Sets a preferred number of commands to batch into a command list before executing the command list. A value of 0 causes the batch size to be adjusted dynamically. A value greater than 0 specifies fixed size batching, with the batch size set to the specified value. The default is 0. |
 | SYCL_PI_LEVEL_ZERO_FILTER_EVENT_WAIT_LIST | Integer | When set to 0, disables filtering of signaled events from wait lists when using the Level Zero backend. The default is 1. |
+| SYCL_PI_LEVEL_ZERO_USE_COPY_ENGINE | Integer | Allows the use of copy engine, if available in the device, in Level Zero plugin to transfer SYCL buffer or image data between the host and/or device(s) and to fill SYCL buffer or image data in device or shared memory. The default is 1. |
 | SYCL_PARALLEL_FOR_RANGE_ROUNDING_TRACE | Any(\*) | Enables tracing of parallel_for invocations with rounded-up ranges. |
 | SYCL_DISABLE_PARALLEL_FOR_RANGE_ROUNDING | Any(\*) | Disables automatic rounding-up of parallel_for invocation ranges. |
 | SYCL_ENABLE_PCI | Integer | When set to 1, enables obtaining the GPU PCI address when using the Level Zero backend. The default is 0. |