Update SDK generator to OpenAPI Generator

[lordofweb]

Description

This PR proposes a major update of the SDK generator by migrating from swagger-codegen to OpenAPI Generator, while maintaining compatibility with the existing SDK structure.

Main changes:

• Migration from swagger-codegen to OpenAPI Generator
• PHP 8.1 support
• Addition of OpenAPI Generator configuration file (config-openapi-generator.yml)
• Creation of custom templates to maintain consistency with previously generated code
• Update of API models and endpoints

Technical benefits:

1. Generated code modernization

   • Full PHP 8.1 support
   • Better strict type handling
   • Cleaner and better documented code

2. Improved maintenance

   • Centralized configuration in config-openapi-generator.yml
   • Custom templates for better generated code control
   • Easier to update with future API versions

3. Best practices

   • Use of latest OpenAPI features
   • Improved documentation
   • Updated unit tests

How to test

To generate the SDK with the new configuration:

openapi-generator generate --skip-validate-spec -c config-openapi-generator.yml

Migration notes

• General SDK structure remains the same to maintain compatibility
• Namespaces and file organization are preserved
• Configuration is now more flexible and documented

Checklist

• [x] OpenAPI Generator configuration set up
• [x] Custom templates created
• [x] PHP 8.1 support added
• [x] Documentation updated
• [x] Existing code structure preserved

[sonarqubecloud[bot]]

Quality Gate failed

Failed conditions
50.2% Duplication on New Code (required ≤ 3%)

See analysis details on SonarQube Cloud