## 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
Optional,
    Sequence,
    Tuple,
    Union,
)
from urllib.parse import urljoin, urlparse
import lzstring
import pytz
from dateutil import parser
from dateutil.relativedelta import relativedelta
from django.conf import settings
from django.core.cache import cache
from django.db.models.query import QuerySet
from django.db.utils import DatabaseError
from django.http import HttpRequest, HttpResponse
from django.template.loader import get_template
from django.utils import timezone
from sentry_sdk import push_scope
from posthog.exceptions import RequestParsingError
from posthog.redis import get_client
DATERANGE_MAP = {
    "minute": datetime.timedelta(minutes=1),
    "hour": datetime.timedelta(hours=1),
    "day": datetime.timedelta(days=1),
    "week": datetime.timedelta(weeks=1),
    "month": datetime.timedelta(days=31),
}
ANONYMOUS_REGEX = r"^([a-z0-9]+\-){4}([a-z0-9]+)$"
__location__ = os.path.realpath(os.path.join(os.getcwd(), os.path.dirname(__file__)))
def format_label_date(date: datetime.datetime, interval: str) -> str: