Front page: Docs updates tab (frontpage_docs_updates.feature)

This file needs additional test to check that "More documentation.." link on the bottom of the tab works.

What was the purpose of having 2 scenarios to check if new book pages show up in the tab? Number of filled fields has no effect on whether page will show up or not, so we could go with just 1 test.

Also can we please rename this file to frontpage_docs_updates.feature.