Added whats-new field to package page.

I believe this is the final piece of new metadata from index-v1 to include in the website.

Above is a screenshot of it with the testy repository. You wont see it in the surge.sh build because the GP repo doesn't include "What's new" and the surge.sh build can't build the entire F-Droid index due to size constraints.

Clearly the formatting of the whats new text suffers from the same formatting problem as the description, so that will be fixed at the same time the description is.

Includes a fix for long app titles from the testy repository which were not wrapping in the sidebar also.