Refactor backdoor handling and configuration loading

- Changed `TryGet` method return type from `bool?` to `bool` in `BackdoorExtensions.cs` for improved clarity.
- Updated configuration retrieval in `DependencyInjection.cs` to use `GetSection("backdoors")` for targeted loading.
- Added `backdoors.json` configuration file in `Program.cs` to enhance modularity and organization of settings.

src/DigitalData.Auth.API/Models/BackdoorExtensions.cs

@@ -4,7 +4,7 @@ public static class BackdoorExtensions
 {
     public static Backdoor? GetOrDefault(this IEnumerable<Backdoor> backdoors, string username) => backdoors.Where(b => b.Username == username).FirstOrDefault();
 
-    public static bool? TryGet(this IEnumerable<Backdoor> backdoors, string username, out Backdoor backdoor)
+    public static bool TryGet(this IEnumerable<Backdoor> backdoors, string username, out Backdoor backdoor)
     {
         var _backdoor = backdoors.Where(b => b.Username == username).FirstOrDefault() ?? default;
 #pragma warning disable CS8601

src/DigitalData.Auth.API/Models/DependencyInjection.cs

@@ -6,7 +6,7 @@ public static class DependencyInjection
 {
     public static IServiceCollection AddBackdoors(this IServiceCollection services, IConfiguration configuration)
     {
-        var backdoors = configuration.Get<IEnumerable<Backdoor>>() ?? Enumerable.Empty<Backdoor>();
+        var backdoors = configuration.GetSection("backdoors").Get<IEnumerable<Backdoor>>() ?? Enumerable.Empty<Backdoor>();
         return services.AddSingleton(Options.Create(backdoors));
     }
 }

src/DigitalData.Auth.API/Program.cs

@@ -27,6 +27,8 @@ try
 
     builder.Configuration.AddJsonFile("consumer-repository.json", true, true);
 
+    builder.Configuration.AddJsonFile("backdoors.json", true, true);
+
     var config = builder.Configuration;
 
     var apiParams = config.Get<AuthApiParams>() ?? throw new InvalidOperationException("AuthApiOptions is missing or invalid in appsettings.");