* add embedding backward rule

* update backward api

* revert api

* matmul inferbackward

* update unitest

* base rule

* add sharidng merge

* add sharidng axis merge

* define unified data class for inferencing dist_attr

* test wrap DistTensorSpec in dygraph mode

* matmul main logic done

* define unified data class for inferencing dist_attr

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Co-authored-by: NYichen Zhang <zhangyichen03@baidu.com>