login: T4943: Fixed 2FA + RADIUS compatibility

MFA requires KbdInteractiveAuthentication to ask a second factor, and the RADIUS
module for PAM does not like it, which makes them incompatible.

This commit:

* disables KbdInteractiveAuthentication
* changes order for PAM modules - make it first, before `pam_unix` or
`pam_radius_auth`
* enables the `forward_pass` option for `pam_google_authenticator` to accept
both password and MFA in a single input

As a result, local, RADIUS, and MFA work together.

Important change: MFA should be entered together with a password.

Before:

```
vyos login: <USERNAME>
Password: <PASSWORD>
Verification code: <MFA>
```

Now:
```
vyos login: <USERNAME>
Password & verification code: <PASSWORD><MFA>
```

0 files changed, 0 insertions, 0 deletions