Always hash storage diff contract addresses

- Enables syncing Geth and Parity diffs with same transformer lookup
- Maybe worth always hashing the storage key so we don't need a hashed
  and not-hashed version in the key lookups?

libraries/shared/transformer/storage_transformer.go

@@ -18,14 +18,13 @@ package transformer
 
 import (
 	"github.com/ethereum/go-ethereum/common"
-
 	"github.com/vulcanize/vulcanizedb/libraries/shared/storage/utils"
 	"github.com/vulcanize/vulcanizedb/pkg/datastore/postgres"
 )
 
 type StorageTransformer interface {
 	Execute(diff utils.StorageDiff) error
-	ContractAddress() common.Address
+	KeccakContractAddress() common.Hash
 }
 
 type StorageTransformerInitializer func(db *postgres.DB) StorageTransformer