Add screenshots for managing 2FA devices in oxTrust

[willow9886]

https://gluu.org/docs/ce/authn-guide/supergluu/#credential-management

Let's add the below screenshot to show managing the users authentication mechanisms in oxTrust in the above section of the docs for the following authentication docs: Super Gluu, U2F, SMS OTP, TOTP/HOTP.

Let's add to 4.0, 3.1.6, 3.1.5, 3.1.4 docs, if possible.