add v2 calendar dtos

BeckmanComms.Api.DataTransferObjects/V2/Events/CalendarDto.cs

+namespace BeckmanComms.Api.DataTransferObjects.V2.Events
+{
+    /// <summary>
+    /// Information describing a webtools calendar.
+    /// </summary>
+    public class CalendarDto
+    {
+        /// <summary>
+        /// Calendar Name.
+        /// </summary>
+        public string Name { get; set; }
+
+        /// <summary>
+        /// Webtools calendar ID.
+        /// </summary>
+        public int CalendarId { get; set; }
+
+        /// <summary>
+        /// Human-readable description of calendar's purpose.
+        /// </summary>
+        public string Description { get; set; }
+    }
+}
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