Streamline start-up instructions in ReadMe

The ReadMe has a list of the commands you need to get started.

• Build the Docker images first thing (using docker-composer build)

• Run the creation of the database tables through docker-compose
  • no-deps ensures the database container is not started
  • overriding entrypoint to bypass the wait Shell script

Bug: T202293
Change-Id: Iaadd6f19c931ebe6363d348d172ebd4a7e023f32