Ground work for Wino Calendar. (#475)

Wino Calendar abstractions.

Wino.Core.Domain/Entities/Calendar/CalendarItem.cs

@@ -0,0 +1,24 @@
+using System;
+using SQLite;
+using Wino.Core.Domain.Enums;
+
+namespace Wino.Core.Domain.Entities.Calendar
+{
+    public class CalendarItem
+    {
+        [PrimaryKey]
+        public Guid Id { get; set; }
+        public string Title { get; set; }
+        public string Description { get; set; }
+        public string Location { get; set; }
+        public DateTimeOffset StartTime { get; set; }
+        public DateTimeOffset EndTime { get; set; }
+        public bool IsAllDay { get; set; }
+        public Guid? RecurrenceRuleId { get; set; }
+        public CalendarItemStatus Status { get; set; }
+        public CalendarItemVisibility Visibility { get; set; }
+        public DateTimeOffset CreatedAt { get; set; }
+        public DateTimeOffset UpdatedAt { get; set; }
+        public Guid CalendarId { get; set; }
+    }
+}