Consistency models with JoliGEN for inpainting

[beniz]

This PR adds support for Consistency Models (https://arxiv.org/abs/2303.01469 and https://arxiv.org/abs/2310.14189).

Usage:

python3 train.py --dataroot /data1/beniz/data/noglasses2glasses_ffhq --checkpoints_dir /home/beniz/checkpoints --name noglasses2glasses --config_json examples/example_cm_noglasses2glasses.json

Example:

Note: some options (and thus doc & examples scripts have been modified) to accomodate the BaseDiffusion main class.