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/utils/core.py

@@ -15,6 +15,7 @@
 # specific language governing permissions and limitations
 # under the License.
 # pylint: disable=C,R,W
+# flake8: noqa I202
 """Utility functions used across Superset"""
 from datetime import date, datetime, time, timedelta
 import decimal
@@ -51,7 +52,11 @@ import markdown as md
 import numpy
 import pandas as pd
 import parsedatetime
-from pydruid.utils.having import Having
+
+try:
+    from pydruid.utils.having import Having
+except ImportError:
+    pass
 import sqlalchemy as sa
 from sqlalchemy import event, exc, select, Text
 from sqlalchemy.dialects.mysql import MEDIUMTEXT
@@ -72,6 +77,25 @@ JS_MAX_INTEGER = 9007199254740991  # Largest int Java Script can handle 2^53-1
 
 sources = {"chart": 0, "dashboard": 1, "sql_lab": 2}
 
+try:
+    # Having might not have been imported.
+    class DimSelector(Having):
+        def __init__(self, **args):
+            # Just a hack to prevent any exceptions
+            Having.__init__(self, type="equalTo", aggregation=None, value=None)
+
+            self.having = {
+                "having": {
+                    "type": "dimSelector",
+                    "dimension": args["dimension"],
+                    "value": args["value"],
+                }
+            }
+
+
+except NameError:
+    pass
+
 
 def flasher(msg, severity=None):
     """Flask's flash if available, logging call if not"""
@@ -179,20 +203,6 @@ def string_to_num(s: str):
         return None
 
 
-class DimSelector(Having):
-    def __init__(self, **args):
-        # Just a hack to prevent any exceptions
-        Having.__init__(self, type="equalTo", aggregation=None, value=None)
-
-        self.having = {
-            "having": {
-                "type": "dimSelector",
-                "dimension": args["dimension"],
-                "value": args["value"],
-            }
-        }
-
-
 def list_minus(l: List, minus: List) -> List:
     """Returns l without what is in minus