refactor: remove utils pkg

BREAKING CHANGE: utils package has been removed in favor of specific new
packages (http, crypto, strings)

pkg/utils/sign.go

@@ -1,27 +0,0 @@
-package utils
-
-import (
-	"encoding/json"
-	"errors"
-
-	"gopkg.in/square/go-jose.v2"
-)
-
-func Sign(object interface{}, signer jose.Signer) (string, error) {
-	payload, err := json.Marshal(object)
-	if err != nil {
-		return "", err
-	}
-	return SignPayload(payload, signer)
-}
-
-func SignPayload(payload []byte, signer jose.Signer) (string, error) {
-	if signer == nil {
-		return "", errors.New("missing signer")
-	}
-	result, err := signer.Sign(payload)
-	if err != nil {
-		return "", err
-	}
-	return result.CompactSerialize()
-}