* first v of vit shardformer
* keep vit
* update
* vit shard add vitattention vitlayer
* update num head shard para
* finish test for vit
* add new_model_class & postprocess
* add vit readme
* delete old files & fix the conflict
* fix sth
* add dropout layer, add dropout test
* modify seed manager as context manager
* add a copy of col_nn.layer
* add dist_crossentropy loss; separate module test
* polish the code
* fix dist crossentropy loss
* add dropout layer, add dropout test
* modify seed manager as context manager
* add a copy of col_nn.layer
* add dist_crossentropy loss; separate module test
* polish the code
* fix dist crossentropy loss