[DOCS] improve "Saving and retrieving data" docs (#417)
[DOCS] improve "Saving and retrieving data" docs (#417)

- 'post' is generally a confusing resource to use in examples do to the action also named POST
- Steps show generating the template multiple times
- Generating a route create a route and a template
- find has been findAll for a long time.
FirebaseExtended/emberfire,FirebaseExtended/emberfire,FirebaseExtended/emberfire,FirebaseExtended/emberfire