Add Modern class with utility methods for readln, writeln and conversions

src/libraries/System.Private.CoreLib/src/System/Modern.cs

@@ -0,0 +1,72 @@
+using System;
+
+namespace System
+{
+    public static class Modern
+    {
+        public static void writeln(object value)
+        {
+            Console.WriteLine(value);
+        }
+        public static void write(object value)
+        {
+            Console.Write(value);
+        }
+        public static string? readln()
+        {
+            return Console.ReadLine();
+        }
+        public static int toint(object value)
+        {
+            return Convert.ToInt32(value);
+        }
+        public static byte tobyte(object value)
+        {
+            return Convert.ToByte(value);
+        }
+        public static short toshort(object value)
+        {
+            return Convert.ToInt16(value);
+        }
+        public static long tolong(object value)
+        {
+            return Convert.ToInt64(value);
+        }
+        public static float tofloat(object value)
+        {
+            return Convert.ToSingle(value);
+        }
+        public static double todouble(object value)
+        {
+            return Convert.ToDouble(value);
+        }
+        public static bool tobool(object value)
+        {
+            return Convert.ToBoolean(value);
+        }
+        public static char tochar(object value)
+        {
+            return Convert.ToChar(value);
+        }
+        public static decimal todecimal(object value)
+        {
+            return Convert.ToDecimal(value);
+        }
+        public static DateTime todatetime(object value)
+        {
+            return Convert.ToDateTime(value);
+        }
+        public static DateOnly todate(DateTime value)
+        {
+            return DateOnly.FromDateTime(value);
+        }
+        public static TimeOnly totime(DateTime value)
+        {
+            return TimeOnly.FromDateTime(value);
+        }
+        public static string tostring(object value)
+        {
+            return value.ToString() ?? string.Empty;
+        }
+    }
+}