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

src/NadekoBot/Common/SmartText/SmartText.cs

@@ -0,0 +1,37 @@
+using Newtonsoft.Json;
+
+namespace NadekoBot
+{
+    // todo 3.3 check if saving embeds in db has IsEmbed field, to prevent rechecking and generating exceptions on every use
+    public abstract class SmartText
+    {
+        public bool IsEmbed => this is SmartEmbedText;
+        public bool IsPlainText => this is SmartPlainText;
+
+        public static SmartText CreateFrom(string input)
+        {
+            if (string.IsNullOrWhiteSpace(input) || !input.Trim().StartsWith("{"))
+            {
+                return new SmartPlainText(input);
+            }
+
+            try
+            {
+                var smartEmbedText = JsonConvert.DeserializeObject<SmartEmbedText>(input);
+
+                smartEmbedText.NormalizeFields();
+
+                if (!smartEmbedText.IsValid)
+                {
+                    return new SmartPlainText(input);
+                }
+
+                return smartEmbedText;
+            }
+            catch
+            {
+                return new SmartPlainText(input);
+            }
+        }
+    }
+}