Add a search function to Engineering best practices

[nprasath002]

Would be useful to have a search function on https://10up.github.io/Engineering-Best-Practices/ to quickly search related items

[tlovett1]

Definite +1

[colorful-tones]

It looks like this client side library is best approach for Jekyll Github Pages site: https://github.com/christian-fei/Simple-Jekyll-Search