[Request] DDIM Inversion implementation

[andreabosisio]

Dear authors and community,

I would like to request the implementation of DDIM Inversion in the codebase -- similarly to what's done in class diffusers.DDIMInverseScheduler.

I have tried to implement DDIM Inversion myself, but I'm facing some challenges in understanding the indexing of noise variables. Additionally, there seems to be a related issue (#136) noted in another open ticket, which is causing me further difficulties.

Could you please let me know if there are any plans to implement DDIM Inversion in the near future? Alternatively, if any community members have already attempted to implement it, I would greatly appreciate if you could provide some guidance or point me to their work. I have already asked for updates in #66 (similar request), without success.

Thanks in advance! I'm happy to contribute to the implementation if needed.