OPENNLP-999: Use JBake for website (thanks to @wcolen), new layout, and logo

[kinow]

Thank you for contributing to Apache OpenNLP.

In order to streamline the review of the contribution we ask you
to ensure the following steps have been taken:

For all changes:

• [ x ] Is there a JIRA ticket associated with this PR? Is it referenced
  in the commit message?

• [ x ] Does your PR title start with OPENNLP-XXXX where XXXX is the JIRA number you are trying to resolve? Pay particular attention to the hyphen "-" character.

• [ x ] Has your PR been rebased against the latest commit within the target branch (typically master)?

• [ x ] Is your initial contribution a single, squashed commit?

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• Have you written or updated unit tests to verify your changes?
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• If applicable, have you updated the LICENSE file, including the main LICENSE file in opennlp folder?
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Note:

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[jzonthemtn]

It looks nice!

[smarthi]

Also add Jeffrey Zemerick (jzemerick) (C) to this list

[kinow]

Oh, also forgot to add myself....

[smarthi]

Daniel Russ is now C-P

[kottmann]

All those files should probably have AL headers when possible.

[kinow]

Pull request updated and squashed.

Team members list updated.

Added headers to most files, except for assets (JQuery JS, CSS files, etc). Comments for AsciiDoc are /// and for FreeMaker are like HTML but start with <#--. These comments do not generate extra blank lines when consumed by the template parser.

Also updated the News article page that was not displaying correctly, and removed news/index.html that was never used (templates/news.ftl gets served instead).

Thanks!
Bruno

[kinow]

Gitpubsub for websites allows static content sites being served from a branch, asf-site by default [1]. We could merge
pull request #182, then have a build job in Jenkins, with the following Maven build step:

# build just the web site module
mvn clean package -pl opennlp-site -am

# given using something like ghp-import could be complicated [2]

git add -A -f opennlp-site/target/opennlp-site/
git commit -m "Update site"
git subtree split --prefix opennlp-site/target/opennlp-site/ -b asf-site
git push -f origin asf-site:asf-site

Trigger the job whenever someone commits to opennlp-site (don't remember the names in Jenkins, but you can filter the commit...). That way that branch would always be up to date. I believe this would not automatically reflect opennlp.apache.org. But instead, gitpubsub would push the site to opennlp.staging.apache.org (not sure though).

[1] https://blogs.apache.org/infra/entry/git_based_websites_available
[2] https://github.com/davisp/ghp-import/blob/master/ghp_import.py