Translate producer-consumer from Golang to Python

[amariucaitheodor]

This PR focuses on translating the producer-consumer image from Golang to Python. The reason for the translation is that Golang is not natively supported by Azure Functions (they only have a work-around where you write a custom handler HTTP server that gets queried by the Azure Function). This wouldn't be a problem in itself if the serverless.com tool supported Golang deployments, but it doesn't either...

Files to be translated include:

• producer-consumer/aws/main.go
• producer-consumer/vhive/main.go
• producer-consumer/common/aws.go
• producer-consumer/common/grpc.go
• producer-consumer/common/main.go
• producer-consumer/common/object-storage.go
• producer-consumer/common/util.go
• producer-consumer/common/util-test.go

[ustiugov]

@anukratb please split up into 1-2day cards