[DC-AE] Add the official Deep Compression Autoencoder code(32x,64x,128x compression ratio);

[lawrence-cj]

What does this PR do?

This PR will add the official DC-AE (Deep Compression Autoencoder for Efficient High-Resolution Diffusion Models) into the diffusers lib. DC-AE first makes the Autoencoder is able to compress images into 32x, 64x, and 128x latent space without performance degradation. It's also an AE used by the powerful T2I base model SANA

Paper: https://arxiv.org/abs/2410.10733v1
Original code repo: https://github.com/mit-han-lab/efficientvit/tree/master/applications/dc_ae

Core library:

• Docs: @stevhliu and @sayakpaul
• General functionalities: @sayakpaul @yiyixuxu @DN6

We want to collaborate on this PR together with friends from HF. Feel free to contact me here. Cc: @sayakpaul

[Abhinay1997]

Looking forward to this @lawrence-cj!