Refactor Metadata Generation to Use YAML-Based Prompt Management

[KunalScriptz]

Description:
This PR refactors the metadata generation process for images and text documents by introducing YAML-based prompt management. Instead of hardcoding prompts directly in the code, all prompts are stored in a prompts.yaml file, which is loaded once and used throughout the application. This enhances maintainability and makes it easier to update or extend prompts in the future.

Changes:
Added prompts.yaml file in the prompts directory, containing structured prompts for image and text processing.
Created a load_prompts function to load YAML prompts at runtime.
Refactored the generate_image_metadata and generate_text_metadata functions to utilize the YAML-based prompts.
Improved dynamic content handling by replacing placeholders (e.g., {{ description }}) in prompts.

Motivation and Context:
This change addresses the need for better prompt management and easier scalability when modifying or adding new prompts. Centralizing the prompt management in a YAML file reduces code duplication and improves the clarity of prompt definitions.

[QiuYannnn]

Thank you for the update. I find the modifications very useful. Could you please pull the latest version from the main branch and modify the code again? I released a new version yesterday with some structural updates.

[KunalScriptz]

Sure, ill work on it.