## Bug description

strtobool is used in several places where it will cause deprecation warning in Pythin 3.10 and error in Python 3.12 since distutils will be removed in Python 3.12 .

Reference : https://www.python.org/dev/peps/pep-0632/

```
rg distutils                     
posthog/api/annotation.py
1:from distutils.util import strtobool

posthog/api/dashboard.py
2:from distutils.util import strtobool

posthog/api/insight.py
1:from distutils.util import strtobool

posthog/models/filters/mixins/common.py
4:from distutils.util import strtobool

posthog/settings.py
17:from distutils.util import strtobool
```

## Expected behavior

It's a good idea to vendor in the function as it's a short one.

## Environment

- [ ] PostHog Cloud
- [ ] self-hosted PostHog, version/commit: _please provide_


#### *Thank you* for your bug report – we love squashing them!

posthog/settings.py
value = os.getenv(key)
    if value is None:
        if optional:
            return None
        if default is not None:
            return default
        else:
            raise ImproperlyConfigured(f'The environment variable "{key}" is required to run PostHog!')
    if type_cast is not None:
        return type_cast(value)
    return value
def get_list(text: str) -> List[str]: