[ci skip] Add back intro README content from 1.x, updated to 2.x syntax.
[ci skip] Add back intro README content from 1.x, updated to 2.x syntax.

JeremybellEU/polymer,JeremybellEU/polymer,ikeagold/polymer,Polymer/polymer,ikeagold/polymer,Polymer/polymer,Polymer/polymer,ikeagold/polymer,JeremybellEU/polymer