Create a new "Join us" page on eclipse.org

The new "join us" page is finally ready for implementation! The figma file can be found here: https://www.figma.com/design/vQWleVU0ZpJ4Nc86tFapCn/Eclipse-Foundation-Website?node-id=1044-657&t=8FVk70WVBPOBTiyG-1. Please let us know if you have any questions!