* Simplify SSZ handling
* fix tests
* add version to SSZ proto and to GetBeaconStateSSZV2
* TestProduceBlockV2SSZ
* rest of tests
* middleware
* use constants
* some middleware changes
* test fix
Co-authored-by: prylabs-bulldozer[bot] <58059840+prylabs-bulldozer[bot]@users.noreply.github.com>