CI job to deploy User docs to Syndesis website

[kahboom]

tl;dr
We need to create a CI job that deploys User docs to the Syndesis website (gh-pages branch via the master branch build).

Background
Per conversation w/ @KurtStam and @zregvart , it would be beneficial to keep the User docs in the main Syndesis app repository, as they currently are, for a few reasons:

• This is what we currently have set up (less work)
• Avoid disrupting the Docs team's existing workflow
• Keeping the user documentation close to the code base fosters community involvement
• Easier alignment with versioning (similar to how Apicurio has set up here with the version dropdown)

So, the setup will be as follows:

• Developer Handbook and other docs (contribution guidelines, quickstarts, etc.) will exist in the Syndesis website repository.
• Community User docs will remain in the main Syndesis app repository. A CI build will deploy the docs to the Syndesis website.

Both types of documentation, on building, will end up on the Syndesis community website. This setup will also be documented on the website. 😂