- The fluffy test vector repo got forked (well, copied rather) to
become the official one under ethereum github org, so we change
to that repo now and archive ours.
- Our repo also stored accumulator / historical_roots, replace
that with a new repo which is only for network configs.
- Several changes needed to be made due to test vectors that got
updated + some of them got changed to / are yaml format instead of
json.