7620: Start removing dependencies on requests (#7643)

* 7620: Start removing dependencies on requests

* Patch urllib.request.urlopen instead of requests.get

* Try to fix flake8

* More work on flake8 import errors

* First attempt at using urllib with cookies

* Fix pylint/flake8

* Fix test_deliver_slice_csv_attachment

* Fix test_deliver_slice_csv_inline

* Import requests and pydruid conditionally, remove dependency on prison

* Fix flake errors

* Fix load_examples

* Please flake

* Skip tests depending on optional deps

* Try to please flake

* Address review comments

* Remove Druid-related UI

* Revert "Remove Druid-related UI"

This reverts commit d7e0f166cc3f3dd2496b4a666e177f0c191aeb0f.

* Skip a few tests more

* Put imports in right order

* Apply black patch

* Please flake

* Please black, silence flake

* Use flake8 silencing the right way

* Add deps for CI

superset/tasks/cache.py

@@ -18,10 +18,10 @@
 
 import json
 import logging
+from urllib import request
+from urllib.error import URLError
 
 from celery.utils.log import get_task_logger
-import requests
-from requests.exceptions import RequestException
 from sqlalchemy import and_, func
 
 from superset import app, db
@@ -282,9 +282,9 @@ def cache_warmup(strategy_name, *args, **kwargs):
     for url in strategy.get_urls():
         try:
             logger.info(f"Fetching {url}")
-            requests.get(url)
+            request.urlopen(url)
             results["success"].append(url)
-        except RequestException:
+        except URLError:
             logger.exception("Error warming up cache!")
             results["errors"].append(url)