Add renderAndDownload() shortcut and support for custom headers

[AdrienGras]

Hello Carbone.io team and contributors,

First of all, thank you for your great work on this project 🙏
Carbone has been a huge time-saver for me when integrating document generation into my applications. I really appreciate the clarity and quality of the SDKs and documentation you provide.

This pull request aims to add a couple of convenience features already available in the Carbone REST API, to make life easier for developers using the PHP SDK.

🔧 Added Features:

renderAndDownload() method:
A shorthand combining render() and download() in one call, using the download=true query param, as described in the Carbone API documentation.

Custom headers support:
This enables advanced features like template conservation durations and webhook configurations, as supported by the Carbone API.

All new logic is covered with unit tests, and I ran PHP CS Fixer to ensure code style consistency across the changes.

The PR #7 is open for review – please feel free to discuss or suggest improvements. I'm happy to iterate on it if needed. Thanks again for your amazing work!

Best regards,

[steevepay]

Thanks Adrian for your message and your PR, I'll take a look and come back to you shortly.
Have a great day!

[neverything]

@steevepay any update on this or anything that is missing that I might be able to help with? Would love to simplify my code with the renderAndDownload()

[steevepay]

Hello,
Sorry for the delay, I take a look in the coming days because yes we already planned to simplify the render and download function with only one HTTP request, instead of two.
I reach back to you asap.