Added docker-compose.yml and Makefile for easier setup of Sandfly.

[nicolaipre]

Hi Craig and Sandfly Team.

As promised to Craig at a recent conference, here is my proposed solution to use docker-compose.yml to set up Sandfly.

This should allow users to more easily get the Sandfly service(s) running without running shell scripts manually.

Workflow:

# Clone repo
$ git clone https://github.com/sandflysecurity/sandfly-setup
$ cd sandfly-setup

# Create .env with your desired settings
$ cp env.example .env

# Initialize sandfly database etc.
$ make init

# Start the services
$ make start

# Bring down containers and remove all data and settings
$ make clean

Although there are still room for improvements, I believe and hope this will draw more users to use Sandfly.

This currently works but it could also be beneficial to move the commands from the Makefile to the container entrypoints instead to make it even more clean.