Add impact index fixture and filesystem artifact uploader

- Introduced a sample BOM index JSON file for impact index testing.
- Created unit tests for the impact index fixture to ensure proper loading of sample images.
- Implemented the FilesystemPackRunArtifactUploader class to handle artifact uploads to the local filesystem.
- Added comprehensive tests for the FilesystemPackRunArtifactUploader, covering file copying, missing files, and expression outputs.

src/Excititor/StellaOps.Excititor.WebService/Program.cs

@@ -18,7 +18,6 @@ using StellaOps.Excititor.Policy;
 using StellaOps.Excititor.Storage.Mongo;
 using StellaOps.Excititor.WebService.Endpoints;
 using StellaOps.Excititor.WebService.Services;
-using StellaOps.Excititor.Core;
 using StellaOps.Excititor.Core.Aoc;
 
 var builder = WebApplication.CreateBuilder(args);