add readme

[ibourgeois]

Context

As a User, I would like to have a README.md to follow installation instructions and usage steps.

As a Developer, I would like to have a README.md to follow setting up a local development environment and contribution instructions.

The instructions can be added later on, after the package is published. For now, it can just include a description of the project.

Acceptance Criteria

• README.md file exists
• README.md contains a basic description of the project