feat: Add Windows Service hosting support

- Add Microsoft.Extensions.Hosting.WindowsServices package
- Add HostingOptions:UseWindowsService configuration flag to appsettings.json
- Configure Program.cs to optionally run as Windows Service based on config
- IIS hosting continues to work by default (UseWindowsService=false)
- Delete obsolete Worker.cs that was conflicting with ProfileManager

ECMJobRunner.WebCron/appsettings.json

@@ -9,6 +9,9 @@
     "SDD-VMP04-SQL17": "Server=SDD-VMP04-SQL17\\DD_DEVELOP01;Database=DD_ECM;User Id=sa;Password=dd;Encrypt=false;TrustServerCertificate=True;"
   },
   "AllowedHosts": "*",
+  "HostingOptions": {
+    "UseWindowsService": false
+  },
   "Hangfire": {
     "InMemory": true
   },