Since both Dependency and Metadata are pseudo-folders with the distinct PascalCase, keep it consistent in the targets too.

Should make it easier moving forward for contributors.

This is a must-have for build and analyzer packages which need to pack their dependencies privately, yet they are authored typically in the same solution as the main library they contribute to, and might need its assets as private (i.e. in an analyzer that uses the types in the main library).

When passing --bl, the most common thing to do after the `nugetize`
operation finishes is to open the generated log to inspect it. So
try to do it automatically by default. Don't fail if we can't open
it automatically via the shell operation.

Since we simulate a DTB, turns out that SourceLink turns itself off during those :). So we must explicitly turn it back on to get these values in the output. They can be useful to troubleshoot whether they are being properly calculated.

This optimizes the case where EmitPackage=false, so it's not necessary to create the folder, and also ensures this works if the task is invoked from other targets.

1. When the restore/build operations are taking too long, start outputing the underlying MSBuild messages to help the user troubleshoot/understand what's happening. This is better than just killing the process as we were doing, which can always be done by doing a Ctrl+Break to stop the process.

2. Render unique dependencies and order dependencies for better layout.

This makes it simpler to just place all items of a given type inside a folder, like:

```xml
<None Update="@(None)" PackagePath="docs" />
```

This would place all None items under the `docs` root package dir, preserving the directory structure in the project underneath that folder.

This matches the behavior in SDK pack and makes sense as a default when IsPackable is set, instead of requiring explicit PackageId,