Improve end-to-end testing

In order to make the testing simpler and more reliable these are the general ideas on how to improve it:

[x] include a MySQL Docker container and a docker-compose
[x] add a Makefile that starts the DB container before running the tests
[x] ingest real pricing data to use it for the tests (?)
[ ] include a real Terraform project, using terraform containers to generate the plan for each of the supported Terraform versions

cycloidio / terracost