Most services are implemented as command/queries

Code cleanup

ModernKeePass.Application/Settings/Queries/GetSettingQuery.cs

@@ -0,0 +1,24 @@
+using MediatR;
+using ModernKeePass.Application.Common.Interfaces;
+
+namespace ModernKeePass.Application.Settings.Queries
+{
+    public class GetSettingQuery<T> : IRequest<T>
+    {
+        public string Key { get; set; }
+
+        public class GetSettingQueryHandler : IRequestHandler<GetSettingQuery<T>, T>
+        {
+            private readonly ISettingsProxy _settingsProxy;
+
+            public GetSettingQueryHandler(ISettingsProxy settingsProxy)
+            {
+                _settingsProxy = settingsProxy;
+            }
+            public T Handle(GetSettingQuery<T> message)
+            {
+                return _settingsProxy.GetSetting<T>(message.Key);
+            }
+        }
+    }
+}