Redesign /copyright to unify the wiki Contributors page

[andrewharvey]

pulling out the discussion from #1480 about changes to the /copyright page to support displaying a large number of contributors/attributions.

...Essentially we simply need to code a solution for this that will remove the current very artificial two tier system, which likely means we will have collapse-able / expandable lists on the copyright page and some way import the contents...

• copyright/attribution notices probably either don't need to be or shouldn't be translated

/cc @simonpoole