Move all the Dockerfiles to a docker folder

This would need a basic understanding of docker. You can refer to how [IntelOwl does it](https://github.com/intelowlproject/IntelOwl/tree/master/docker) just in a little less complicated way because we don't have too many services as of now. The project is still in its nascent stage so it should be fairly simple. I will appreciate it if someone takes this issue up.

The files to shift are of course `Dockerfile` and `Dockerfile.celery`