co-contributed with 夕陌&雨泓

 * add torch epoch based trainer and dis utils
 * add hooks including optimizer, lrscheduler, logging, checkpoint, evaluation, time profiling
 * add torch mdoel base and test
 * add optimizer and lrscheduler module
 * add sbert for text classification example
 * add task_dataset for dataset-level processor

Link: https://code.alibaba-inc.com/Ali-MaaS/MaaS-lib/codereview/9338412

Link: https://code.alibaba-inc.com/Ali-MaaS/MaaS-lib/codereview/9316720

* make audio requirements optional
 * add changelog for version v0.2
 * add numpy constraint for compatibility with tensorflow1.15
 * update faq
 * fix nlp requiring tensorflow
 * add torchvision to multimodal dependency
 * bump version from 0.2.1 to 0.2.2
 * add warning msg when tensorflow is not installed
 
Link: https://code.alibaba-inc.com/Ali-MaaS/MaaS-lib/codereview/9268278

1.  refactor maaslib to modelscope
2.  fix UT error
3.  support pipeline which does not register default model

Link: https://code.alibaba-inc.com/Ali-MaaS/MaaS-lib/codereview/8988388