Add RecVAE model

[flywithu]

Description

Add the option to use RecVAE model

Checklist:

• I have added tests.
• I have updated the documentation accordingly.
• I have updated README.md (if you are adding a new model).
• I have updated examples/README.md (if you are adding a new example).
• I have updated datasets/README.md (if you are adding a new dataset).

[tqtg]

Thanks for the contribution. This is great!

Glancing at the RecVAE model, I do notice that it shares a lot of similarities with some models that we have in Cornac (e.g., VAECF). Is it possible that you can restructure your code accordingly so we can better review and maintain? There are multiple utilities which can be reused instead of developing from scratch.

[flywithu]

Thanks for the contribution. This is great!

Glancing at the RecVAE model, I do notice that it shares a lot of similarities with some models that we have in Cornac (e.g., VAECF). Is it possible that you can restructure your code accordingly so we can better review and maintain? There are multiple utilities which can be reused instead of developing from scratch.

"Thank you for your opinion. I will make the necessary revisions based on your request, referencing vaecf."

[flywithu]

I've removed duplicate code such as batch code.

[tqtg]

hey @flywithu, this looks good to me overall. I just have a few comments above that can be easily addressed. Thanks again for this great contribution.

[flywithu]

hi @tqtg
Thank you for your review and comments. I have also learned new.