Refactor `EditRoute` & `CloneRoute` preprocessors

[MustafaSaber]

Is your feature request related to a problem? Please describe. @AlexanderYastrebov: I think the whole edit/clone business would be much simpler if we serialize route to eskip, replace string and parse it back

Additional context (optional) Add any other context or screenshots about the feature request here.

Would you like to work on it? not now.