Add 'reasonable_range' field to schema files

[GernotMaier]

Model parameter schema currently include an allowed_range for values, e.g. for num_gains it is:

allowed_range:
      min: 1
      max: 2

We discussed to adding another field called reasonable_range (is this a good name?) to indicate the range of parameter values reasonable for CTA.

(and above example is not a good example for this!)

[orelgueta]

Agree that this is needed. Just want to add that a value which is outside the reasonable_range should raise a warning and not an error.

[GernotMaier]

This is easy to implement. Which parameters are good examples to add this?

Anyone with good examples from the model parameters? (altitude.schema.yml is probably reasonable in a range of 0-8000m.)