docs: update docs for open source

[wenytang-ms]

The work item is https://ossmsft.visualstudio.com/Reviews/_workitems/edit/48790 https://docs.opensource.microsoft.com/releasing/ according to this docs, update these files

[formulahendry]

Current LICENSE file if EULA, so we need to switch to MIT license file:

• Rename current LICENSE file to EULA file
• Create LICENSE file with MIT
• Create a section in README, and pointed to EULA file