chalklab/Dataset-NIST-TRC-MySQL: Release v1.1 - Addition of Docker TRC MySQL Image

Added Docker image creation via a GitHub Action. This is stored on the GitHub Container Registry (ghcr.io) and made available in this repository as a package. Specific changes are:

• Creation of a Dockerfile that defines the process of building the Docker image (starting from a mysql image on Dockerhub)
• Creation of a GitHub Workflow that runs the Dockerfile to create the image and then stores in on ghcr
• Replacement of database files as .zip with .gz versions, which allows the Dockerfile ADD command on line 21 to send the SQL gzip file to the image and decompress it at the same time