* Move domain function and all signing root functions from beacon-chain/core/helpers to beacon-chain/core
* @terencechain suggestion to put these methods under core/signing
* Add block and attestation to container pkg
* Move aggregation into attestation
* Update attestation_test.go
* Move them to proto
* Gazelle
* fix cycle
Co-authored-by: prylabs-bulldozer[bot] <58059840+prylabs-bulldozer[bot]@users.noreply.github.com>
Co-authored-by: Raul Jordan <raul@prysmaticlabs.com>