Docker support (#8725)

* Moving Docker stuff around

* docker-compose working as expected

* Updating README

* Addressing comments

* Utilizing requirements-extra

docker/pythonpath_dev/.gitignore

@@ -0,0 +1,23 @@
+#
+# Licensed to the Apache Software Foundation (ASF) under one or more
+# contributor license agreements.  See the NOTICE file distributed with
+# this work for additional information regarding copyright ownership.
+# The ASF licenses this file to You under the Apache License, Version 2.0
+# (the "License"); you may not use this file except in compliance with
+# the License.  You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+
+# Ignore everything
+*
+# DON'T ignore the .gitignore
+!.gitignore
+!superset_config.py
+!superset_config_local.example