* system setting to disable password login

* fix linter warning

* fix indentation warning

* Prohibit disable-password-login if no identity providers are configured

* Warnings and explicit confirmation when en-/disabling password-login

- Disabling password login now gives a warning and requires a second
  confirmation which needs to be explicitly typed.
- (Re)Enabling password login now also gives a simple warning.
- Removing an identity provider while password-login is disabled now
  also warns about possible problems.

* Fix formatting

* Fix code-style

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Co-authored-by: traumweh <5042134-traumweh@users.noreply.gitlab.com>