Add background service and update project configuration

Added a `Worker` class as a hosted background service to log
periodic messages. Updated `DigitalData.EmailProfiler.API.csproj`
to include `UserSecretsId` for secure development storage and
added `Microsoft.Extensions.Hosting` package. Replaced the
`Controllers` folder reference with `Properties`. Updated
`Program.cs` to register the `Worker` service, enable API
exploration, and retain Swagger configuration.

src/DigitalData.EmailProfiler.API/DigitalData.EmailProfiler.API.csproj

@@ -4,14 +4,16 @@
     <TargetFramework>net8.0</TargetFramework>
     <Nullable>enable</Nullable>
     <ImplicitUsings>enable</ImplicitUsings>
+	<UserSecretsId>dotnet-DigitalData.EmailProfiler.Service-e7ef6a9a-436f-48a1-b4f6-ec9381c8cb47</UserSecretsId>
   </PropertyGroup>
 
   <ItemGroup>
     <PackageReference Include="Swashbuckle.AspNetCore" Version="6.6.2" />
+	<PackageReference Include="Microsoft.Extensions.Hosting" Version="8.0.1" />
   </ItemGroup>
 
   <ItemGroup>
-    <Folder Include="Controllers\" />
+    <Folder Include="Properties\" />
   </ItemGroup>
 
 </Project>

src/DigitalData.EmailProfiler.API/Program.cs

@@ -1,9 +1,10 @@
-var builder = WebApplication.CreateBuilder(args);
+using DigitalData.EmailProfiler.API;
 
-// Add services to the container.
+var builder = WebApplication.CreateBuilder(args);
+builder.Services.AddHostedService<Worker>();
 
 builder.Services.AddControllers();
-// Learn more about configuring Swagger/OpenAPI at https://aka.ms/aspnetcore/swashbuckle
+
 builder.Services.AddEndpointsApiExplorer();
 builder.Services.AddSwaggerGen();
 

src/DigitalData.EmailProfiler.API/Worker.cs

@@ -0,0 +1,16 @@
+namespace DigitalData.EmailProfiler.API;
+
+public class Worker(ILogger<Worker> Logger) : BackgroundService
+{
+    protected override async Task ExecuteAsync(CancellationToken stoppingToken)
+    {
+        while (!stoppingToken.IsCancellationRequested)
+        {
+            if (Logger.IsEnabled(LogLevel.Information))
+            {
+                Logger.LogInformation("Worker running at: {time}", DateTimeOffset.Now);
+            }
+            await Task.Delay(1000, stoppingToken);
+        }
+    }
+}