Update to dotnet 9.0, add user roles, MatchStats and OpenApi/Scalar in dev

LaDOSE.Src/LaDOSE.Entity/ApplicationUserRole.cs

@@ -0,0 +1,16 @@
+namespace LaDOSE.Entity
+{
+    /// <summary>
+    /// The <c>applicationuserrole</c> join table. Declared explicitly rather than left
+    /// implicit so its columns match the table that already exists in the database
+    /// (<c>userid</c>, <c>roleid</c>, no surrogate key).
+    /// </summary>
+    public class ApplicationUserRole
+    {
+        public int UserId { get; set; }
+        public ApplicationUser User { get; set; }
+
+        public int RoleId { get; set; }
+        public ApplicationRole Role { get; set; }
+    }
+}