feat: IConfiguration for system and other configurations

Engine.Core/Config/IConfiguration.cs

@@ -0,0 +1,23 @@
+using System.Collections.Generic;
+
+namespace Engine.Core.Config;
+
+public interface IConfiguration
+{
+    static IConfiguration System { get; set; } = new SystemConfiguration();
+    static IConfiguration Shared { get; set; } = new BasicConfiguration();
+
+    Event<IConfiguration, ConfigUpdateArguments> OnAdded { get; }
+    Event<IConfiguration, ConfigUpdateArguments> OnSet { get; }
+    Event<IConfiguration, ConfigUpdateArguments> OnRemoved { get; }
+
+    IReadOnlyDictionary<string, object?> Values { get; }
+
+    bool Has(string key);
+    object? Get(string key);
+    T? Get<T>(string key, T? defaultValue = default);
+    void Set<T>(string key, T value);
+    void Remove<T>(string key);
+
+    readonly record struct ConfigUpdateArguments(string Key);
+}