[management] set default values in comment in the gravitee.yml

[NicolasGeraud]

The configuration in comment in the gravitee.yml must be the default value. For the rating feature and the support feature, the default value is false but the value in comment is true.

Expected Behavior

Because false is the default value, this must be the value in comment in the gravitee.yml

[aelamrani]

I think we should indicate on the comment of the configuration attribute the default value. This way, the user who change the value will keep the default value on comment...