camel-yaml-dsl - Add backwards compatible loading of older routes/kamelets

In Camel 3.15 we fixed the route model in yaml dsl to be aligned to the core model DSL.

However this meant that a route "steps" was moved into its correct place, as child to a from.

However Camel K users will struggle to migrate, so lets make the yaml-dsl parser able to detect the old style and auto-correct this and log a WARN about deprecated style in use.