[SYCL][COMPAT] Added utility headers to syclcompat (#11086)

SYCLcompat primary goals and features are documented
[here](https://intel.github.io/llvm-docs/syclcompat/README.html).

The PR includes the helper utility functions for complex datatypes,
logical groups or vectorized operations, among others.

---------

Co-authored-by: Joe Todd's <[email protected]>
Co-authored-by: Pietro Ghiglio's <[email protected]>

Author: 3 people

sycl/include/syclcompat/syclcompat.hpp

@@ -29,3 +29,4 @@
 #include <syclcompat/kernel.hpp>
 #include <syclcompat/launch.hpp>
 #include <syclcompat/memory.hpp>
+#include <syclcompat/util.hpp>