add keys endpoint

pkg/alexandra/fredclients.go

pkg/alexandra/middleware.go

pkg/api/api.go

pkg/fred/exthandler.go

pkg/fred/storeservice.go

pkg/proxy/api.go

proto/Dockerfile

proto/client/client.pb.go

proto/client/client.proto

proto/client/client_grpc.pb.go

proto/client/client_pb2.py

proto/client/client_pb2.pyi

proto/client/client_pb2_grpc.py

proto/middleware/middleware.pb.go

proto/middleware/middleware.proto

proto/middleware/middleware_grpc.pb.go

proto/middleware/middleware_pb2.py

proto/middleware/middleware_pb2.pyi

proto/middleware/middleware_pb2_grpc.py

tests/3NodeTest/cmd/main/standard_suite.go