Removed duplicate declaration of the deploy plugin.
Switched to the prepare-package phase for the documentation generation as the declaration of the Maven Build Helper Plugin caused the unpacking of the dependencies to be delayed to after the asciidoctor execution which then renders the CSS and JavaScript files missing.
Extracted the JavaDoc generation settings into the plugin management section so that both the CI build as well as the one creating the JavaDoc for the site deployment use the same setup. Removed the JavaDoc declaration from the default build and activate it in the testing build.
Removed inclusion of Spring Data static resources as they're superseded by the docs resources.
Introduces pipeline that replaces the Bambook Spring HATEOAS one which builds on master branch and deploys to artifactory.
Additionally:
* Tests against JDK 8, 11, and 12 before doing the final build and deploy.
* Also handles pull requests, running same suite of tests against mutiple JDKs.
