- Loader is renamed `configure_invokeai.py`, but `preload_models.py` is retained
(as a shell) for backward compatibility
- At startup, if no runtime root directory exists and no `.invokeai` startup file is
present, user will be prompted to select the runtime and outputs directories.
- Also expanded the number of initial models offered to the user to include the
most "liked" ones from HuggingFace, including the two trinart models, the
PaperCut model, and the VoxelArt model.
- Created a configuration file for initial models to be offered to the user, at
configs/INITIAL_MODELS.yaml
