Support table for sample-label (#1977)
Support table for sample-label (#1977)

* support table for label

* fix ut

* add unit test

* add doc

* update

intel-analytics/BigDL,intel-analytics/BigDL,yangw1234/BigDL,yangw1234/BigDL,yangw1234/BigDL,intel-analytics/BigDL,intel-analytics/BigDL,yangw1234/BigDL