Created readme for JS folder.
Created readme for JS folder.

Now that there are two versions supported, made subfolders for each and made note.
Esri/developer-support,Esri/developer-support,Esri/developer-support,hhkaos/developer-support,hhkaos/developer-support,Esri/developer-support,hhkaos/developer-support,Esri/developer-support,hhkaos/developer-support,Esri/developer-support,hhkaos/developer-support,hhkaos/developer-support,hhkaos/developer-support,hhkaos/developer-support,Esri/developer-support,Esri/developer-support,Esri/developer-support,Esri/developer-support,hhkaos/developer-support,Esri/developer-support,Esri/developer-support,hhkaos/developer-support,Esri/developer-support,hhkaos/developer-support