test publish atr-maven-plugin doc as html

[hboutemy]

pushing content from https://github.com/apache/tooling-atr-maven-plugin/tree/gh-pages = https://apache.github.io/tooling-atr-maven-plugin/

to test if the rendering at https://tooling.apache.org/atr/maven/ is good: in that case, we can switch from github.io to here

[dave2wave]

I don't want all of this on the tooling-docs website. I would consider a high level view. I'll accept the maven plugin docs in GitHub pages.