JSON Generated by audit with --json not valid

Please mention the following:
- What command was run?
python cloudmapper.py audit --accounts ${successful_accounts} --json --minimum_severity $MINIMUM_ALERT_SEVERITY

- Are you working out of a pipenv environment, Docker, or something else?
Docker

The JSON generated by this command is not easily loadable again to an object or list due to the fact that each finding is a newline of JSON that's not in a list.

While you could sanitize it seems easier to make sure the STDOUT is standard JSON. Ideally it would be a list.

```
[
{},
{},
{}
]
```

If this sounds good I know where to make the appropriate changes.
This is foundational to support report generation from audit data already collected.