Hide two-factor auth filter in activities

[MorrisJobke]

• disable "Two-factor authentication" if none of those apps are enabled
• see Disable activity filters based on enabled apps activity#150

cc @ChristophWurst

[LukasReschke]

Maybe just move this to a generic "security" category where we also could show logins and so on?

[ChristophWurst]

Maybe just move this to a generic "security" category where we also could show logins and so on?

Fine by me. Where should I put that code? Currently I've added the generic 2fa stuff to the backup codes app, but that doesn't really fit for generic security activities.

@LukasReschke @nickvergessen should I add a security, security_activity, activity_security or similar app?

[nickvergessen]

I'd say add it to the settings app, which already handles activities for email and password change:
https://github.com/nextcloud/server/blob/master/settings/Application.php#L115

[ChristophWurst]

Maybe just move this to a generic "security" category where we also could show logins and so on?

Login activities sound like a nice enhancement. We could publish an activity whenever a browser session or device token is created. This is, however, something for NC13 I assume.