Doc improvement, refactoring, tests and new features

This PR brings the following changes:

• Improve the documentation and comments
• Improve OpenAPI doc
• Improve logs
• Add a separate docker-compose.yml for the platforms (Pulsar and MongoDB)
• Add a basic SDC CLI
• Add unit tests for contract models
• Add integration tests for EPP
• Add a script to generate secrets
• Add a script to deploy the Custodian on a local Kubernetes cluster
• Fix vulnerable dependencies
• Fix error caused by expose sections in docker-compose.yml files