Apply formatting incrementally

`dotnet format` is currently difficult to enable on a large existing project in an incremental way that creates small, reviewable change sets. The most notable example is the `whitespace` command, which cannot be broken down any further (unlike specific diagnostics which can be fixed individually), and which apples all whitespace formatting rules regardless of whether they are explicitly configured in the `.editorconfig` file or not.

Two changes that would make this process much easier:

1. Break out "whitespace" changes into individual categories (e.g. indent, newline, brace style, etc) that can be fixed individually in the same way that diagnostics can.
1. Add the capability (either a new command or an option for existing commands) to only fix things that are explicitly configured in the `.editorconfig`.

These changes would significantly improve the incremental implementation experience.