Fix #3961

Not a serious issue because they are meaningless past single use

Allow access to account settings, 2FA, authorized applications, and
account deletions to unconfirmed and pending users, as well as
users who had their accounts disabled. Suspended users cannot update
their e-mail or password or delete their account.

Display account status on account settings page, for example, when
an account is frozen, limited, unconfirmed or pending review.

After sign up, login users straight away and show a simple page that
tells them the status of their account with links to account settings
and logout, to reduce onboarding friction and allow users to correct
wrongly typed e-mail addresses.

Move the final sign-up step of SSO integrations to be the same
as above to reduce code duplication.

Define `Settings::BaseController#set_body_classes` so that sub classes
inherit `Settings::BaseController` don't need to define
`#set_body_classes` agein.

* Fix #3910 - Require OTP authentication to disable 2FA. Also, remove ability
to generate new OTP backup codes *after* initial backup codes were handed
out during activation

* Restore recovery code re-generation

* Improve display of some 2FA elements

* Add spec coverage for settings/two_factor_auth area

* extract setup method for qr code

* Move otp required check to before action

* Merge method only used once

* Remove duplicate view

* Consolidate creation of @codes for backup

* Move settings/2fq#recovery_codes to settings/recovery_codes#create

* Rename settings/two_factor_auth#disable to #destroy

* Add coverage for the otp required path on 2fa#show

* Clean up the recovery codes list styles

* Move settings/two_factor_auth to settings/two_factor_authentication

* Reorganize the settings two factor auth area

Updated to use a flow like:

- settings/two_factor_authentication goes to a #show view which has a button
  either enable or disable 2fa on the account
- the disable button turns off the otp requirement for the user
- the enable button cycles the user secret and redirects to a confirmation page
- the confirmation page is a #new view which shows the QR code for user
- that page posts to #create which verifies the code, and creates the recovery
  codes
- that create action shares a view with a recovery codes controller which can be
  used separately to reset codes if needed