Renaming DIPS Cond Att to CADS + Adding option to load optimiser

This MR does the following:

• Renaming all Dips Cond att things to CADS.
• If a model is now loaded (for continuing the training), the optimizer is now also loaded correctly and not freshly compiled.
• Adding the load_optimiser option (per default True). When loading a model, you can decide if the optimiser is loaded from the model file (for continuing a training) or a new optimiser is initialised (use the model as start point for a new training).
• Documentation for the new load_optimiser option is added.