* 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
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.
Kim De Mey