Edit/expand ODK JavaRosa page

This doc is very spartan at the moment, and mentions sections that have yet to be written.

It either needs to be expanded, or (if that isn't going to happen) edited to only talk about what is actually there.

Start with the existing ODK JavaRosa documentation page referenced by the issue and compare its text with the sections it mentions but does not contain. Decide whether the page can be expanded or should be narrowed to existing content; done means the page no longer promises unwritten sections and accurately reflects the available documentation.

Written by the indexing model from the issue text.