sparse feature importance support by DeepRec

[welsonzhang]

System information

• DeepRec version (you are using): 1.15.5+deeprec2208
• Are you willing to contribute it (Yes/No): Yes

Describe the feature and the current behavior/state. how deeprec analyze the sparse feature importance ? just like https://github.com/PaddlePaddle/PaddleRec/blob/master/doc/feature_importance.md https://github.com/PaddlePaddle/PaddleRec/blob/master/tools/feature_importance.py

it will shuffle sparse slots in the dataset, then eval. Comparing the baseline AUC and the AUC after slot_shuffle, the greater the AUC decrease, the more important the feature.

Will this change the current api? How?

Who will benefit with this feature? it help to analyze the sparse feature importance

Any Other info.