FEATURE: New Lockdown and Account On Hold Page

When a site is in level 2 lockdown, the entire frontend becomes inaccessible. The admin is available, but only to sysadmins. If a non-sysadmin attempts to login, it will send them to the AccountOnHold.aspx page as well.

This is what people will see during a lockdown. Level 1 means that only non-sysadmins attempting to access the admin console will see this. Level 2 means all frontend users and non-sysadmins will see it The registered date, expired on, and lockdown level only appears when logged in to the admin console.

Also implemented the white labeling settings necessary to customize this page. Highlighted areas
can be customized.