Provide "good" password rules

As a user, I expect to have all the information I need to fill the registration form. Unfortunately, it happens that there are constraints on the password that aren't explicitly given. Since the main rule is "minimum 10 characters" (unless configured differently), I expect this rule at least to be shown in the form. I suggest the following label: "Your password must contain at least %{min_length} characters, must not be too common (e.g. 123456) and must be different from your nickname and your email." (where min_length is passed via NOBSPW.configuration.min_password_length)