Deprecate and remove project-list in eclipsefdn_projects

As discussed here, we need to have the ability to add classes on the .project-list element so we can modify column sizes and breakpoints.

https://gitlab.eclipse.org/eclipsefdn/it/webdev/hugo-solstice-theme/-/blob/main/layouts/shortcodes/eclipsefdn_projects.html#L26

Also, remove the function in js/src/research/projects-section.js from eclipse.org's repo. This should no longer be needed with this change.