Add Docker support for running the app

[SalmaAlassal]

This PR introduces Docker support for the Calculator application, making it easier to deploy and run the app in a consistent environment across different systems.

Changes include:

• Adding a Dockerfile to build a Docker image for the application.
• Adding a docker-compose.yml file to simplify running the container.
• Updating the requirements.txt file to include two additional dependencies.
• Updated the README.md to include instructions for running the application using Docker.