Configure verbose logging to off by default

The current default user configuration for bst is:

```
logging:
verbose: true
```

I don't think this makes sense for most users even if it can make sense for Ci systems. Having to instruct every user to turn this off is a bigger hassle than configuring one CI system per project to turn this config on, in my opinion.

Locate the default user configuration for bst and find where logging.verbose is set. Check for tests covering default logging or configuration behavior, then change the default to false while preserving the ability for CI systems to enable it explicitly; done means ordinary users no longer receive verbose logging by default.

Written by the indexing model from the issue text.