Track the project name for a generator driver and report it via ETW

[chsienki]

When there are multiple projects building in parallel (such as in a VS solution) the current generator telemetry doesn't allow you to know from which project each invocation of the generator is coming from.

This adds an optional value to the generator options where a caller can add a project name. It populates that from the tooling to pass in the project name + id.

[dotnet-policy-service[bot]]

This PR modifies public API files. Please follow the instructions at https://github.com/dotnet/roslyn/blob/main/docs/contributing/API%20Review%20Process.md for ensuring all public APIs are reviewed before merging.

[333fred]

API Review

• We're not sure if projectName is sufficient, or appropriate for the compiler layer to handle
  • Does ETW support passing a dictionary
  • Even if it doesn't, there's nothing saying this needs to go to ETW. It could go to some other logging framework.
• What about a dictionary of properties?
  • We don't want a general series of properties, as this is the general generator options. Needs to be specific.
  • IdentificationProperties: used by the generator driver to identify itself in logging frameworks.

Conclusion: API Approved:

  -     public GeneratorDriverOptions(IncrementalGeneratorOutputKind disabledOutputs = IncrementalGeneratorOutputKind.None, bool trackIncrementalGeneratorSteps = false, string? baseDirectory = null)
  +     public GeneratorDriverOptions(IncrementalGeneratorOutputKind disabledOutputs = IncrementalGeneratorOutputKind.None, bool trackIncrementalGeneratorSteps = false, string? baseDirectory = null, ImmutableDictionary<string, string?>? identificationProperties = null)