Port Revisiting Web Components with Dojo blog post from learn-dojo

[matt-gadd]

Port https://learn-dojo.com/web-components-with-dojo-revisted/ over to dojo site, and update any parts where necessary to make sure the content is current. We should also consider renaming this to "Creating Custom Elements with Dojo" or something similar, rather than "revisiting".

Make sure the blog post is authored by whoever picks this up and Rene Rubalcava, with a cross-link at the bottom back to the original post.