docs(contributing): update contributing guidelines with new hooks script
docs(contributing): update contributing guidelines with new hooks script

also adds references to the code of conduct and the licensing site.

UW-Madison-DoIT/uw-frame,UW-Madison-DoIT/uw-frame,thevoiceofzeke/uw-frame,uPortal-Project/uportal-app-framework,thevoiceofzeke/uw-frame,paulerickson/uw-frame,thevoiceofzeke/uw-frame,paulerickson/uw-frame,paulerickson/uw-frame,uPortal-Project/uportal-app-framework,UW-Madison-DoIT/uw-frame,uPortal-Project/uportal-app-framework