Validation of policy settings

[PVince81]

• prevent pointless settings, see send notification when passwords are about to expire #27 (comment)
• prevent empty special chars list: Special character list can be empty when "Define special characters" is checked #26
• hide second checkbox when first is not checked

@phil-davis @jvillafanez @pmaier1 for later

[PVince81]

• disallow "0", empty string or negative values in any of the number fields

Note: on modern browsers the fields are treated as numbers, so this at least prevents to have negative values due to the "min" settings and also string values are prevented. Non-modern browsers might allow for it.

In general, the backend must validate these and refuse

[PVince81]

From what I see most of the fields have "min='0'", need to check on a case by case basis.