Add README file to explain project features

Related to #5

Add a README file to the repository to explain the project's features and usage.

Project Description: Describe the project, including its purpose and the types of data it manages.
Project Features: List the main features of the project, such as table creation, trigger creation, data insertion, and data retrieval.
Database Setup Instructions: Provide instructions for creating a database user and connecting to the database.
SQL Script Execution Instructions: Provide step-by-step instructions for executing the various SQL scripts in the repository.
Script Explanations: Explain the purpose of each SQL script in the repository.
Contact Information: Provide contact information for further assistance.

For more details, open the Copilot Workspace session.

devEddu17x / proyecto-db-4to-ciclo