Adds ga_appname config setting and require current token to enable/disable gauth

Fixes #31 

Requires current gauth token in order to enable/disable gauth. This seems to be the standard/most secure way to handle 2FA.
BTW you may need to update the yml translations file to include these ``enabled`` / ``disabled`` keys. I forgot to include it in the PR, but it basically should say:

```
        enabled: "2 Factor Authentication successfully enabled!"
        disabled: "2 Factor Authentication successfully disabled!"
```