WIP: Add new settings and reorder settings based on docs

[RehanSaeed]

Fixes #60, #73, #46

• Adds the new settings. Marked them all with # NEW to make them easy to find.
• Reorders the settings based on the .NET docs.
• Updated the links to the .NET docs.
• Adds Visual Studio spell checker settings (Note that the locale will be customizable in the dotnet new template).
• Deprecate old severity syntax as per https://github.com/dotnet/roslyn/issues/44201.

[nathanielcutajar]

Is there by any chance an ETA for the release of this MR? Or are there still other changes to be made?

[LucaMahler]

What is the state of this PR?