* reworked some of the das core specs, pr'd to check whether whether the conflicting type issue is centric to my machine or not
* bumped nim-blscurve to 9c6e80c6109133c0af3025654f5a8820282cff05, same as unstable
* bumped nim-eth2-scenarios, nim-nat-traversal at par with unstable, added more pathches, made peerdas devnet branch backward compatible, peerdas passing new ssz tests as per alpha3, disabled electra fixture tests, as branch hasn't been rebased for a while
* refactor test fixture files
* rm: serializeDataColumn
* refactor: took data columns extracted from blobs during block proposal to the heap
* disable blob broadcast in pd devnet
* fix addBlock in message router
* fix: data column iterator
* added debug checkpoints to check CI
* refactor if else conditions
* add: updated das core specs to alpha 3, and unit tests pass
* electra attestation updates
In Electra, we have two attestation formats: on-chain and on-network -
the former combines all committees of a slot in a single committee bit
list.
This PR makes a number of cleanups to move towards fixing this -
attestation packing however still needs to be fixed as it currently
creates attestations with a single committee only which is very
inefficient.
* more attestations in the blocks
* signing and aggregation fixes
* tool fix
* test, import
With checkpoint sync, the checkpoint block is typically unavailable at
the start, and only backfilled later. To avoid treating it as having
zero hash, execution disabled in some contexts, wrap the result of
`loadExecutionBlockHash` in `Opt` and handle block hash being unknown.
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Co-authored-by: Jacek Sieka <jacek@status.im>