Generate a notification to generate backup codes if you enable an other
2FA provider but backup codes are not yet generated.
* Add event listner
* Insert background job
* Background job tests and emits notification every 2 weeks
* If the backup codes are generated the next run will remove the job
Signed-off-by: Roeland Jago Douma <roeland@famdouma.nl>
This adds persistence to the Nextcloud server 2FA logic so that the server
knows which 2FA providers are enabled for a specific user at any time, even
when the provider is not available.
The `IStatefulProvider` interface was added as tagging interface for providers
that are compatible with this new API.
Signed-off-by: Christoph Wurst <christoph@winzerhof-wurst.at>