Which token to provide for hangouts google chat config?

Per documentation:
```
If you dont use BotMan Studio, add these line to $config array that you pass when you create the object from BotManFactory.

'hangouts' => [
'token' => 'YOUR-WEBHOOK-TOKEN',
]
```

What is the webhook token? I have a token for certain room, but for user to bot communication, no token is needed and in the console settings only HTTPS URL is required to be provided and no token is given

Start with the documented `hangouts` configuration passed to BotManFactory and compare the `token` guidance with the Hangouts Chat console settings described in the issue. Done means the documentation clearly explains whether a webhook token is needed for room and user-to-bot communication, and what value users should provide.

Written by the indexing model from the issue text.