Find an easy way to extend or duplicate the eclipse.org mega menu links

When updating the menu items for eclipse.org, we also need to make that change to the boilerplate, and any website that uses it.

We should facilitate this process by providing a way to inherit the mega menu across different repos.

Host a menu.toml in hugo-solstice-theme or the boilerplate which gets copied by every site at build time. This could just be an addition to the package.json scripts.

This would solve our issue with Hugo.

If we want to solve this issue across other stacks, such as Drupal, React, Jekyll, etc., we may need to ship the HTML of the navbar from a server.

cc @cguindon