tests(cucumber): add certification

adds certification cucumber test

end2end-tests/cucumber-features/certification.feature

+@genesis.wot
+
+Feature: Certification
+
+    Scenario: Dave certifies Alice
+        When dave certifies alice
+        Then alice should be certified by dave
+
+    @ignoreErrors
+    Scenario: Dave certifies Alice (but dave is not certified by charlie, this test should fail)
+        When dave certifies alice
+        Then dave should be certified by charlie
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