…nique_ptr<__result_and_scratch_storage_base>

…add ability to move sycl::event into __future constructor

…orage + fix usages

…extract from __result_and_scratch_storage internal implementation __result_and_scratch_storage_impl

…extract from __result_and_scratch_storage internal implementation __result_and_scratch_storage_impl - move up some internal data

…extract from __result_and_scratch_storage internal implementation __result_and_scratch_storage_impl - remove __result_and_scratch_storage_data_ptr_t type

…extract from __result_and_scratch_storage internal implementation __result_and_scratch_storage_impl - pass sycl::queue by reference into result_and_scratch_storage

…remove extra else

…introduce __create_usm_buffer and remove some duplicated code

…rename is_USM() to __has_supports_USM_device()

…refactoring of __use_USM_host_allocations()

…remove extra else in __future::get() method

…remove extra else in __future::__get_data() method

…remove extra __future::__future(...)

…fix compile errors

…implementation if USM / Sycl buffers placement based on std::variant

…move the definition of __usm_or_buffer_accessor into __result_and_scratch_storage