Support profiles pages direct access

[JalilArfaoui]

• add a Koa server to serve both static pages generated by Gatsby and dynamic profiles pages
• remove bulle-extension.js and integrate directly within website / profiles code

• better integration between website and profiles …

  Still needs to be done

  • Finish the webserver setup with SSR and bundle serving, and make it all work
  • Ideally, profiles should be part of website app

Closes #1188