Standardise Mechanism for Auto-Detecting Docker Image Build Requisite #50
Description
When creating a new project with project-init and enabling Docker integration, the default project control code always rebuilds the Docker image, unless the user explicitly specifies the PROJECT_CONTAINER_IMAGE_BUILD environment variable introduced in Issue#14.
Introduce a default mechanism by which Docker-related project control code can detect whether the image needs to be rebuilt. Maybe add content change detection for the file content of the Dockerfile.