Add Javadoc to the website

[cmelchior]

The Javadoc for this library should also be visible from the website, either merged into the Realm API or as as a separate link. I'll probably prefer a second link, so

* API Reference

// gets converted to

* Realm API Reference
* Android Adapters API Reference

[stk1m1]

I looked into the website and checked if I could make change. The part that creates API Reference is universal for every binding. i.e. We, Java team, can make a change from API Reference to Realm API Reference, but it will stand out. I'd suggest checking with other bindings as well.

Android Adapters API Reference can be Java specific though.