Added SmartText and inheritors SmartPlainText and SmartEmbedText which will replace CREmbed in the future

src/NadekoBot/Common/SmartText/SmartPlainText.cs

@@ -0,0 +1,23 @@
+namespace NadekoBot
+{
+    public sealed class SmartPlainText : SmartText
+    {
+        public string Text { get; set; }
+
+        public SmartPlainText(string text)
+        {
+            Text = text;
+        }
+
+        public static implicit operator SmartPlainText(string input)
+            => new SmartPlainText(input);
+
+        public static implicit operator string(SmartPlainText input)
+            => input.Text;
+
+        public override string ToString()
+        {
+            return Text;
+        }
+    }
+}