Modified range save method behavior

Now range use the method save of his father and the metric configuration id became a attribute
of it.

save params method was implemented to help during the save model method
Fixed acceptance test for range

signed-off-by: Diego Araujo <diegoamc90@gmail.com>
Some methods on entity range needed to be public.

signed-off-by: Renan Fichberg <rfichberg@gmail.com>