Fixes #16334

Ensure that all *.*proj, *.props, and *.targets files are prefixed with the xml and copyright elements

Clean up the remaining solutions to have the utilities included.

* moving naming styles types into the workspace layer.
Teaching abstract options serialization service about naming styles.

* Implementing naming styles support for editorconfig

* responding to david's PR feedback

* responding to Jason's feedback

* responding to Jason's feedback part 2

* addressing the latest set of comments from David

* addressing Jason's comments

* addressing Kevin's comments

The dependency projects were added as a way to help unify our project.json references.  Instead of every project referencing the NuGet package, we had a dependency project which referenced it and everyone referenced that dependency project.  Due to the transitive nature of NuGet it would be roughly equivalent.

This system had a number of downsides:

1. There was no enforcement.  Even though dependency projects existed, there was no mechanism to force developers to use them.
2. Getting the granularity correct was tricky.
3. The projects themselves have special props / targets to get them to produce no output.  This can trip up MSBuild up to date checks.

Since then though we've begun using RepoUtil to verify our NuGet reference correctness.  This removed the need for these projects and hence I'm removing them from our build.

Signature help improvements for C# tuples (renamed to work around jenkins issues)

TLDR: artifacts are going to move around in Binaries\Debug and the directory is going to get a lot bigger.

At a high level build projects can be classified into three categories based on how they write output:

- incorrect: a given output path is written to more than once with different contents
- less correct: a given output path is written to more than once but always with the same content
- correct: a given output path is written to exactly once

Today the roslyn build is decidedly “incorrect” as pretty much every file is written directly into Binaries\Debug. This means it ends up writing pretty much every Visual Studio SDK DLL twice: once for Dev14 and once for Dev15. For example at various points in the build Binaries\Debug\Microsoft.VisualStudio.Text.Data.dll may refer to Dev14 and at others it’s Dev15. If this seems like a scary proposition for a build that’s because it is indeed scary and it has real consequences. By now pretty much everyone on the team has hit the build race condition that is dragging down our PRs.

The general fix here is to move build outputs into separate directories. Instead of building to $(Configuration) projects now build into say $(Configuration)\Exes\$(MSBuildProjectFileName). This will have a substantial increase in the size of Binaries. We will be looking into ways to reduce that. In the short term though build stability far outweighs the size increase.

This change takes us most of the way to "correct". There are several places I had to compromise in order to get this initial change in:

- UnitTests still build to a common output folder (one for Dev14, another for Dev15). Pulling unit tests apart is going to take a bit of work.
- Every project has a <RoslynProjectType> entry. This will go away in the future for most projects. It's temporarily needed so I can fix roslyn-internal in parallel without taking down the build.
- VSL.Imports.targets is messy. Unavoidable for now due to the above. It will get cleaner as I iterate on this.

None of these are relevant to the underlying race condition. Hence it's okay to push them off.