Update Docs: OVA Initial password not correct

[dreng]

Context

I just downloaded the OVA. The docs at https://docs.graylog.org/en/4.0/pages/getting_started/web_console.html#connect say "If using the VM appliance, log in using admin for both the username and password".

This is not correct actually. As stated here the password is shown in the console of the VM.