New features and updated functionalities

1. Starting frame with the COS training method is now the default scene frame start, instead of frame 1
2. New option for outwards facing cameras with the COS training method
3. Revised file and folder output structure: the output convention follows the original NeRF synthetic dataset structure. The output folder contains the transforms.json files directly, alongside a train folder with images
4. Enabled support for the original NeRF transforms.json file format convention (alongside the Instant NGP file convention)
5. Enabled option to save a log file containing all the necessary information for reproducibility on a BlenderNeRF run