[csv upload] Use python's named temp file (#9047)

* [csv upload] Use python's named temp file

* [csv upload] stream write uploaded file

* Added missing ensure that configured path exists

* Fix, lint

* [csv upload] remove python's tmp file default delete behaviour

superset/db_engine_specs/base.py

@@ -34,7 +34,6 @@ from sqlalchemy.ext.compiler import compiles
 from sqlalchemy.sql import quoted_name, text
 from sqlalchemy.sql.expression import ColumnClause, ColumnElement, Select, TextAsFrom
 from sqlalchemy.types import TypeEngine
-from werkzeug.utils import secure_filename
 
 from superset import app, sql_parse
 from superset.utils import core as utils
@@ -357,9 +356,6 @@ class BaseEngineSpec:  # pylint: disable=too-many-public-methods
         :param kwargs: params to be passed to DataFrame.read_csv
         :return: Pandas DataFrame containing data from csv
         """
-        kwargs["filepath_or_buffer"] = (
-            config["UPLOAD_FOLDER"] + kwargs["filepath_or_buffer"]
-        )
         kwargs["encoding"] = "utf-8"
         kwargs["iterator"] = True
         chunks = pd.read_csv(**kwargs)
@@ -394,7 +390,8 @@ class BaseEngineSpec:  # pylint: disable=too-many-public-methods
                 extension is not None and extension[1:] in config["ALLOWED_EXTENSIONS"]
             )
 
-        filename = secure_filename(form.csv_file.data.filename)
+        filename = form.csv_file.data.filename
+
         if not _allowed_file(filename):
             raise Exception("Invalid file type selected")
         csv_to_df_kwargs = {