Refactor MAISI Network with New Generative AI Components

[KumoLiu]

There are several tasks to refactor MAISI network based on new Generative AI components and move to the MONAI/network

1. Remove Generative Dependency

• [x] remove generative dependency in DiffusionModelUNetMaisi
• [x] remove generative dependency in ControlNetMaisi
• [x] remove generative dependency in AutoencoderKlMaisi

2. Ensure Compatibility of Tutorials and Scripts

• [x] Ensure maisi_diff_unet_training_tutorial.ipynb and corresponding scripts work as before.
• [x] Ensure maisi_train_controlnet_tutorial.ipynb and corresponding scripts work as before.
• [x] Ensure maisi_train_vae_tutorial.ipynb and corresponding scripts work as before.
• [x] Ensure inference work as before.
• [ ] Update state_dict to be compatible with the latest components
• [ ] Update maisi bundle

[KumoLiu]

cc @guopengf @Can-Zhao @dongyang0122 @mingxin-zheng @Nic-Ma