This migration is necessary since Lua scripts sources use the UTF-8 encoding while the web browser sees the iso-8859-1 encoding, and this incongruence breaks the visualization of some non-ascii characters.
- Do now show the "Not Assigned" group in user pool dropdown
- Show an alert message when creating a Captive Portal user and no pools are defined
- Improve unique member validator to account missing network prefixes
- Prevent deleting an Host Group when a captive portal user is defined on it