Added theme saving. Added interfaces for overview pages. Renamed sidebar interface function

Moonlight.ApiServer/Http/Controllers/Admin/Sys/ThemeController.cs

@@ -0,0 +1,24 @@
+using System.Text.Json;
+using Microsoft.AspNetCore.Mvc;
+using MoonCore.Extended.PermFilter;
+using MoonCore.Helpers;
+using Moonlight.Shared.Http.Requests.Admin.Sys;
+
+namespace Moonlight.ApiServer.Http.Controllers.Admin.Sys;
+
+[ApiController]
+[Route("api/admin/system/theme")]
+public class ThemeController : Controller
+{
+    [HttpPatch]
+    [RequirePermission("admin.system.theme.update")]
+    public async Task Patch([FromBody] UpdateThemeRequest request)
+    {
+        var themePath = PathBuilder.File("storage", "theme.json");
+
+        await System.IO.File.WriteAllTextAsync(
+            themePath,
+            JsonSerializer.Serialize(request.Variables)
+        );
+    }
+}