Update existing PHP and Hugo templates with eclipse.org new look and feel

Once we've implemented the base styles for our new look and feel in solstice which we are tracking via eclipsefdn/it/webdev/solstice-assets#330 (closed), we will need to update our existing PHP and Hugo templates to allow us to share a preview with the community on staging in January.

I will publish a blog post introducing our new look and feel to the community and ask them to provide feedback.