Add maxAuthAge to GoogleAuthConfig

#### What
The old `OpenID` supported `max_auth_age` so that we could force a user to re-authenticate if they had not been seen in awhile by Google. This adds `maxAuthAge` to `GoogleAuthConfig`.


#### Why
I am currently switching over `facia-tool` to use `play-googleauth`.
One requirement we have is that we don't want users to stay logged in after a long period of inactivity. Once this expires, we want them to re-authenticate. Without this setting, when the session expires the user would be sent to Google to re-authenticate and would transparently be logged in. With it they are forced to enter their password.

How the user ends up going through the Google auth process is left to the app.

For example, if this was set to `0` and the app never redirected back to Google because it thinks a session is still valid, then this session would stay logged in in the app.
If this was not set, the user sees nothing and just gets transparently logged in when they are sent to re-authenticate.