* Add headers with proof content type and use it for verification
- Add BlockHeaderWithProof content type & content
- Use BlockHeaderWithProof content to verify if chain data is
part of the canonical chain
- Adjust parser & seeder code to be able to seed these headers
with proof
- Adjust eth_data_exporter to be able to export custom header
ranges for which to build proofs (mostly for testing)
There is currently quite some ugliness & clean-up needed for which
a big part is due tos upporting both BlockHeader and
BlockHeaderWithProof on the network.
* Change accumulator proof to array / SSZ vector type
- Change accumulator proof to SSZ vector instead of SSZ list.
- Add and use general buildProof and buildHeaderWithProof func.
* Make the BlockHeaderWithProof an SSZ Union with None option
* Update portal-spec-tests to master commit
- Can write epoch accumulators to files now with eth_data_exporter
- RPC requests to gossip epoch accumulators now uses these files
instead of building on the fly
- Other build accumulator calls are adjusted and only used for
tests and thus moved to testing folder
Portal master accumulator was removed from the network specs as a
content type shared on the network, as since the merge this is
a finite accumulator (pre-merge only).
So in this PR the accumulator gets removed as network type and
gets instead baked into the library. Building it is done by
seperate tooling (eth_data_exporter).
Because of this a lot of extra code can be removed that was
located in history_network, content_db, portal_protocol, etc.
Also removed to option to build the accumulator at start-up
of fluffy as this takes several minutes making it not viable.
It can still be loaded from a provided file however.
The ssz accumulator file is for now stored in the recently
created portal-spec-tests repository.
Also requires us to split header data propagation from block body
and receipts propagation as the now fixed bug would allow for more
data to be gossiped even when data does not get validated (which
requires the headers).
Kim De Mey