feature: added open api merger

[adrrf]

This pull request introduces functionality to merge OpenAPI specifications and serve the merged documentation via a Swagger UI. The changes include new dependencies, configuration updates, and the addition of several new functions and modules to handle the OpenAPI merging and serving process.

Dependencies and Configuration:

• Added openapiv3 and walkdir dependencies to Cargo.toml.
• Updated config.yaml.example to include docs_path and openapi_path for OpenAPI documentation paths.

New Modules and Functions:

• Added openapi module to src/config/mod.rs to handle OpenAPI-related functionality.
• Introduced OpenApiMerger struct in src/config/openapi.rs for merging OpenAPI specifications and generating Swagger UI.
• Updated src/config/parser.rs to include docs_path and openapi_path in GatewayConfig struct.

Main Application Changes:

• Imported OpenApiMerger and added merge_openapi_specs function in src/main.rs to merge specs and generate Swagger UI. [1] [2] [3]
• Added routes in handle_request function to serve OpenAPI spec and Swagger UI.

HTML Template:

• Added openapi.html template for serving Swagger UI.

[Copilot]

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Files not reviewed (1)

• config.yaml.example: Language not supported