Add a block for Adoptium news on the main page

[smlambert]

While we await the launch of the new website, it will be beneficial to make room for important news or marketing on the current main page of adoptium.net. In this way, we can stop using the banner for such items but still reserve real-estate on the very high-traffic main page for directing visitors to current events such as the Security Case study, the upcoming Adoptium Summit and so forth. This real-estate should be for Adoptium-related stories and content.

This new area can share the real-estate currently given to the Adoptium Working Group block at the bottom of the main page.