Setup app logger in python environment

The user's functions can now use `current_app.logger`, and use
`kubectl logs` to see the logs that the function outputs.

examples/python/requestdata.py

@@ -1,5 +1,8 @@
 from flask import request
+from flask import current_app
 
 def main():
     msg = "%s %s:\n---HEADERS---\n%s\n--BODY--\n%s\n-----\n" % (request.method, request.path, request.headers, request.get_data())
+    current_app.logger.info(msg)
+
     return msg