refactor: move database-related projects to a separate folder

SqlData/Persistence/DbInitializer.cs

@@ -0,0 +1,11 @@
+using Microsoft.EntityFrameworkCore;
+
+namespace Mirea.Api.DataAccess.Persistence;
+
+public static class DbInitializer
+{
+    public static void Initialize(DbContext dbContext)
+    {
+        dbContext.Database.EnsureCreated();
+    }
+}