Update docs.microsoft.com for latest changes

[vlada-shubina]

Update documentation before publishing latest changes to website:
Documentation page: https://docs.microsoft.com/en-us/dotnet/core/tools/dotnet-install-script

#118

• deprecate --runtime-id
• add --os

[bekir-ozturk]

Update features brought by aka.ms links: quality option, for instance.

[bekir-ozturk]

Related changes regarding --runtime-id and --os options are proposed in PR dotnet/docs#22453

[bekir-ozturk]

Related PR is now merged. Closing this since aka.ms link issue #12 is on hold at the moment.