Add rate limiting

[michaeldev5]

Description

This PR introduces a significant enhancement to the project by implementing rate limiting and API key functionality, along with the integration of reCAPTCHA verification during the API key generation process. These additions collectively enhance security, prevent abuse, DDOS attacks and ensure controlled access to the API.

Main Contributions

• Implemented rate limiting mechanisms within the backend, controlling the number of HTTP requests to the API within a specified time frame.
• Introduced API key generation and management functionality, allowing users to generate and utilize API keys for authorized access to the API.
• Integrated reCAPTCHA verification during the API key generation process, ensuring that requests are made by legitimate users.
• Added sensitive variables into .env file

Requests Limitations

• Users without an API key have a limit of 20 requests per minute.
• Once an API key is generated, users with the API key can make up to 100 requests per minute.

Note

• The generated API key must be included in the X-API-KEY header of all subsequent API requests to ensure proper authorization and access control.
• Before starting a nest.js application make sure you have .env file created

[dudo50]

This PR will be addressed after 10th August.