Migrate EF websites to our new preview framework

Related to eclipsefdn/helpdesk#1978 (closed)

Additional Requirements. This website had a few re-direct configured with netlify which we need to migrate to nginx:

[[redirects]]
  from = "/xmlns/*"
  to = "https://docs.osgi.org/xmlns/:splat"
  status = 301
  force = true #COMMENT: ensure that we always redirect

[[redirects]]
  from = "/javadoc/*"
  to = "https://docs.osgi.org/javadoc/:splat"
  status = 301
  force = true #COMMENT: ensure that we always redirect

[[redirects]]
  from = "/specification/*"
  to = "https://docs.osgi.org/specification/:splat"
  status = 301
  force = true #COMMENT: ensure that we always redirect

[[redirects]]
  from = "/download/*"
  to = "https://docs.osgi.org/download/:splat"
  status = 301
  force = true #COMMENT: ensure that we always redirect