feat: IConfiguration for system and other configurations

Engine.Core/Config/SystemConfiguration.cs

@@ -0,0 +1,11 @@
+namespace Engine.Core.Config;
+
+public class SystemConfiguration : BasicConfiguration, IConfiguration
+{
+    public SystemConfiguration()
+    {
+        foreach (System.Collections.DictionaryEntry entry in System.Environment.GetEnvironmentVariables())
+            if (entry is { Key: string key, Value: not null })
+                Set(key, entry.Value);
+    }
+}