reuse sticky property from main cookie

When a user wants to stay logged in, the two factor auth is saved for 3
months (main login is saved for a year)

added custom OTP form field

This also fixes wilminator/dokuwiki-plugin-twofactor#26

style adjustment

make 2fa login more recognizable

streamline language files

We use "two-factor" and "mechanism" as our preferred terms now.

fixed language files for settings

changed how provider setup works

This makes the interface a bit cleaner and less confusing

some cleanup and streamlining for providers

make tolerance easier to override in config

removed obsolete config and language

fix error in admin when plugin is not ready, yet

finished admin refactoring

fix handling of multiple providers

first start with the admin interface

disable the user temporarily in all non-main screens

This requires the new DOKUWIKI_INIT_DONE event introduced in
splitbrain/dokuwiki#3640

delete cookie on logout

use action to register providers

fix user checking in preprocess

profile localization and styling

manage optouts

show proper links for alternative providers

fix cookie security

The cookie is now tied to the provider and cookie secret. This way it
can not be constructed without inside knowledge.

Removed old code

The basic mechanisms have been reimplemented, so the old code has been
removed.

handle user default providers

remember 2fa authentications