* add save model for step

* add PS/Collective support , add definition in yaml.md

* add check for QueueDataset while saving by step, modify dnn config yaml as an example

* add logging about model save operation

* fix bug for adding check for QueueDataset, modify dnn config yaml

* fix bug for dnn model config yaml

* fix bug for checking QueueDataset

* fix UT fail

* fix UT fail
Co-authored-by: Ntangwei12 <tangwei12@baidu.com>

* fix demo

* fix

* fix

* fix code style

* add textcnn_pretrain

* add textcnn_pretrain

* change classification to textcnn

* add readme in paddlerec

* add cluster running

* add k8s/paddle cloud

* fix local cluster without gpu

* define engine to train/infer/local_cluster_train/cluster_train

* fix gpu cluster wait

* fix bug for 2ps 2tr
Co-authored-by: Ntangwei <tangwei12@baidu.com>

* fix gpu default card & doc

* update table

* update

* update tdm origin

* update link

* update yaml

* update doc & tdm

* fix tdm multi gpu support