Update Matlab tutorial with Cedric's function

[jules32]

With this, we can update the matlab tutorial, move it out of in-development, and also add a subset of code to the How-Tos section 🎉

From Cedric:

Please find attached the function that handles the dual authentication EarthData/AWS and the script that demonstrates how to use it.

(Attaching these as .txt files, altered from their original .m so I can upload to github)

loadAWSCredentials.txt demoAccess.txt

[jules32]

Updated tutorial: https://mathworks-my.sharepoint.com/:w:/p/cwannaz/EdO51MvnuyBDqBMLcwcmvrEB_vumytIdwTVm2qUGOgA3ZA?rtime=0CvOUFKY20g