Started the Split

Split Json data models coming from REST Api, from the Database models
storing them in a SQLite database.
Work to re-engineer endpoints to use Database objects, and copy/update
data from the json objects.
More work is needed.

FreeTubeSync/Model/Database/Setting.cs

@@ -0,0 +1,10 @@
+using System.ComponentModel.DataAnnotations;
+
+namespace FreeTubeSync.Model.Database;
+
+public class Setting
+{
+    [Key]
+    public string _id { get; set; }
+    public string value { get; set; }
+}