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

Link: https://code.alibaba-inc.com/Ali-MaaS/MaaS-lib/codereview/9165402

This reverts commit c8e2e6de0e.

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

1. refine quick start and pipeline doc
2. remove tf pytorch easynlp from requirements
3. lazy import for torch and tensorflow
4. test successfully on linux and mac intel cpu
5. update api doc

Link: https://code.alibaba-inc.com/Ali-MaaS/MaaS-lib/codereview/8882373

1. add build_doc linter script
2. add sphinx-docs support
3. add development doc and api doc
4. change version to 0.1.0 for the first internal release version

Link: https://code.aone.alibaba-inc.com/Ali-MaaS/MaaS-lib/codereview/8775307