Add support for the vectorize decorator in numba-dpex

[diptorupd]

Numba has a decorator vectorize that allows creation of a NumPy ufunc. The feature was previously partially supported in numba-dpex, but broke around the 0.20 release (refer: #807). The existing code was removed completely from the numba-dpex repo in #1298.

The enhancement request is to evaluate a design for the vectorize decorator in numba-dpex and propose an implementation based on numba-dpex 0.22 APIs.