feat: support nulls in the csv uploads (#10208)

* Support more table properties for the hive upload

Refactor

Add tests, and refactor them to be pytest friendly

Use lowercase table names

Ignore isort

* Use sql params

Co-authored-by: bogdan kyryliuk <bogdankyryliuk@dropbox.com>

superset/forms.py

@@ -15,12 +15,27 @@
 # specific language governing permissions and limitations
 # under the License.
 """Contains the logic to create cohesive forms on the explore view"""
+import json
 from typing import Any, List, Optional
 
 from flask_appbuilder.fieldwidgets import BS3TextFieldWidget
 from wtforms import Field
 
 
+class JsonListField(Field):
+    widget = BS3TextFieldWidget()
+    data: List[str] = []
+
+    def _value(self) -> str:
+        return json.dumps(self.data)
+
+    def process_formdata(self, valuelist: List[str]) -> None:
+        if valuelist and valuelist[0]:
+            self.data = json.loads(valuelist[0])
+        else:
+            self.data = []
+
+
 class CommaSeparatedListField(Field):
     widget = BS3TextFieldWidget()
     data: List[str] = []