Add Nerfstudio renderer module for preview rendering

[wdxia134]

Closes #5

Context:
A need was identified to integrate Nerfstudio for preview rendering in the project. The previous approach did not handle rendering efficiently or offer an easy way to upload rendered images. This PR addresses that gap by introducing a new module.

Changes:

• Added nerfstudio_renderer.py in src/preview_renderer/.
• The script initiates a subprocess call to a Nerfstudio rendering script.
• Includes functionality for uploading the rendered images post-processing.

Technical Reasoning:
By invoking Nerfstudio via subprocess, the integration maintains the modularity of the process and isolates rendering from other components, ensuring better maintainability. The upload function ensures rendered content is immediately accessible for further steps.

Testing Notes:

• To test, run the Nerfstudio rendering process and verify the output images are generated and uploaded correctly.
• Ensure the subprocess executes as expected in your environment.

Feedback welcome!