tests(cucumber): add certification

adds certification cucumber test

end2end-tests/README.md

@@ -55,8 +55,8 @@ Each scenario is a list of steps. In our context (blockchain), only the `When` a
 
 List of possible actions:
 
-- transfer: `alice send 5 ĞD to bob`
-- transfer_ud: `alice send 3 UD to bob`
+- transfer: `alice sends 5 ĞD to bob`
+- transfer_ud: `alice sends 3 UD to bob`
 - transfer_all: `alice sends all her ĞDs to bob`
 
 #### Then