Migrate io.cucumber.java8.Scenario and io.cucumber.java8.Status

Scenario and Status are the only io.cucumber.java8 types with an io.cucumber.java counterpart; the language interfaces such as En and the LambdaGlue body types have none, so renaming the package wholesale would point whatever the migration could not convert at a type that does not exist. Where such a body type does survive it also still expects the cucumber-java8 Scenario, as in an anonymous HookBody, so leave both types be until the last of the lambda glue is gone.