Please update documentation with more details on training the other midas backbones

[MalekWahidi]

I have been trying to train a new ZoeDepth_N model on the NYUv2 dataset with the more efficient DPT_SwinV2_L_384 MiDaS backbone for real-time performance. However, it is not clear from the current documentation about how to properly setup the dataset and config parameters. I have no idea where to find the "shortcuts/datasets/nyu_depth_v2/official_splits/test/". The train_mono script is just printing the config params and does nothing else. What am I missing?