This commit introduces DevContainers based on quickstart, improving the handling of the development environment.
Ports 80 (quickstart project) and 8025 (mailhog) are forwarded within the DevContainer setup. This enhances connectivity and ease of access for local development and debugging with frontend services running inside the container.

Introduce a new "build:dev" script in the frontend package.json to allow parallel builds. Modify related development commands in frontend-sdk and elements to use the correct "build:dev" command. Adjust docker-compose setup to run the new "build:dev" script.

Simplify the Nginx setup by removing the elements-nginx service and directly serving static files from the main Nginx container. Updated volume mounts and configuration to reflect these changes.

…cture

Moved dev containers related files to .devcontainer for better organization and simplified path references in devcontainers-full-setup.yaml.

The /mail/ proxy location block has been deleted from the devcontainer-nginx.conf file.