Support adding customized jars after pip install; fix release related (#2083)
Support adding customized jars after pip install; fix release related (#2083)

* support add jars

* meet review

* fix

* append sys.path

* update

* refactor and fix

* add docs

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