feat: add 1 chapter of course

[ibtyog]

Wakacyjne wyzwanie solvro (backend)
rozdział 1 podstawy api

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Important

Adds a new chapter on API basics for backend development, covering network basics, API concepts, REST principles, and tools like NestJS and Postman.

• New Chapter:
  • Adds Podstawy-API.mdx with content on API basics for backend development.
  • Covers network basics, web application structure, and backend roles.
• API Concepts:
  • Explains API, REST principles, path naming, headers, methods, status codes, query parameters, and JSON.
• Tools and Frameworks:
  • Introduces developer tools, NestJS setup, and Solvro Config.
  • Provides examples of creating a controller and service in NestJS.
  • Discusses Postman for API testing.
• Resources:
  • Includes links to additional materials and a homework assignment.

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