Introduction to vectorization with Vector128 and Vector256 (#84115)

Co-authored-by: Günther Foidl <gue@korporal.at>
Co-authored-by: Dan Moseley <danmose@microsoft.com>
Co-authored-by: Rob Hague <rob.hague00@gmail.com>
Co-authored-by: Tanner Gooding <tagoo@outlook.com>
Co-authored-by: Stephen Toub <stoub@microsoft.com>
Co-authored-by: Jeff Handley <jeffhandley@users.noreply.github.com>