Review and Refine documentation

[scarlett2018]

During the operation on the MS deployments, we found some of the documentation are still hard to be consumed by first time users. This issue is to review and refine current doc for admin/user/ops jump start.

Merge #2000 here.

[sotetsuk]

Link to "Submit a job in Visual Studio Code" in README.md is expired:

https://github.com/Microsoft/vscode-tools-for-ai/blob/master/docs/quickstart-05-pai.md

[squirrelsc]

Link to "Submit a job in Visual Studio Code" in README.md is expired:

https://github.com/Microsoft/vscode-tools-for-ai/blob/master/docs/quickstart-05-pai.md

Thanks for reporting, we will fix it in next releases. For VS code extension, please refer to below page.
https://github.com/Microsoft/pai/tree/master/contrib/pai_vscode

[fanyangCS]

related issues.
#1938
#1794

[scarlett2018]

@squirrelsc - I had changed this issue into an Epic, you can splits it into sub items that can fit your pace.

[fanyangCS]

closed and tracked in #4023.