## Bug description

We've had a user create a funnel with Korean characters and 17 steps, which causes this issue:
![image](https://user-images.githubusercontent.com/1727427/120301818-8c212a00-c2cd-11eb-8b00-7ba242e4a9ab.png)

## Expected behavior

We should send requests to api/insight/funnel using POST instead of GET.

## How to reproduce

1.
2.
3.

## Environment

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

## Additional context



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

posthog/utils.py
at_location = email.find("@")
        if at_location == -1:
            return False
        return self.emails.get(email[(at_location + 1) :], False)
def get_available_timezones_with_offsets() -> Dict[str, float]:
    now = dt.datetime.now()
    result = {}
    for tz in pytz.common_timezones:
        try:
            offset = pytz.timezone(tz).utcoffset(now)
        except Exception:
            offset = pytz.timezone(tz).utcoffset(now + dt.timedelta(hours=2))
        if offset is None:
            continue
        offset_hours = int(offset.total_seconds()) / 3600
        result[tz] = offset_hours
    return result
def str_to_bool(value: Any) -> bool:
    """Return whether the provided string (or any value really) represents true. Otherwise false.
    Just like plugin server stringToBoolean.
    """
    if not value:
        return False
    return str(value).lower() in ("y", "yes", "t", "true", "on", "1")
def print_warning(warning_lines: Sequence[str]):
    highlight_length = min(max(map(len, warning_lines)) // 2, shutil.get_terminal_size().columns)
    print("\n".join(("", "🔻" * highlight_length, *warning_lines, "🔺" * highlight_length, "",)), file=sys.stderr)