3406: Master Key: Implements errors and warnings from the specification r=irevoire a=dureuill
<sub>Now in technicolor</sub>
# Pull Request
## What does this PR do?
- Uses `atty` and `termcolor` as dependency
- Use these dependencies to print colored background for warning messages
- Update messages to match https://github.com/meilisearch/specifications/pull/209
## PR checklist
Please check if your PR fulfills the following requirements:
- [ ] Does this PR fix an existing issue, or have you listed the changes applied in the PR description (and why they are needed)?
- [ ] Have you read the contributing guidelines?
- [ ] Have you made sure that the title is accurate and descriptive of the changes?
Thank you so much for contributing to Meilisearch!
Co-authored-by: Louis Dureuil <louis@meilisearch.com>
