* initial implementation
* get committee for epoch
* test
* fix failing test
# Conflicts:
# beacon-chain/rpc/prysm/v1alpha1/validator/assignments_test.go
* combine function arguments
* review feedback
* use sync committee setter
* fix failing test
* fix build
* remove bad test
* refactor for single responsibilities
* radek suggestions
Co-authored-by: prylabs-bulldozer[bot] <58059840+prylabs-bulldozer[bot]@users.noreply.github.com>
Co-authored-by: Raul Jordan <raul@prysmaticlabs.com>
