Ground work for Wino Calendar. (#475)

Wino Calendar abstractions.

Wino.Core.Domain/Entities/Mail/MailAccountAlias.cs

@@ -0,0 +1,63 @@
+using System;
+using SQLite;
+
+namespace Wino.Core.Domain.Entities.Mail
+{
+    public class RemoteAccountAlias
+    {
+        /// <summary>
+        /// Display address of the alias.
+        /// </summary>
+        public string AliasAddress { get; set; }
+
+        /// <summary>
+        /// Address to be included in Reply-To header when alias is used for sending messages.
+        /// </summary>
+        public string ReplyToAddress { get; set; }
+
+        /// <summary>
+        /// Whether this alias is the primary alias for the account.
+        /// </summary>
+        public bool IsPrimary { get; set; }
+
+        /// <summary>
+        /// Whether the alias is verified by the server.
+        /// Only Gmail aliases are verified for now.
+        /// Non-verified alias messages might be rejected by SMTP server.
+        /// </summary>
+        public bool IsVerified { get; set; }
+
+        /// <summary>
+        /// Whether this alias is the root alias for the account.
+        /// Root alias means the first alias that was created for the account.
+        /// It can't be deleted or changed.
+        /// </summary>
+        public bool IsRootAlias { get; set; }
+
+        /// <summary>
+        /// Optional sender name for the alias.
+        /// Falls back to account's sender name if not set when preparing messages.
+        /// Used for Gmail only.
+        /// </summary>
+        public string AliasSenderName { get; set; }
+    }
+
+    public class MailAccountAlias : RemoteAccountAlias
+    {
+        /// <summary>
+        /// Unique Id for the alias.
+        /// </summary>
+        [PrimaryKey]
+        public Guid Id { get; set; }
+
+        /// <summary>
+        /// Account id that this alias is attached to.
+        /// </summary>
+        public Guid AccountId { get; set; }
+
+        /// <summary>
+        /// Root aliases can't be deleted.
+        /// </summary>
+        public bool CanDelete => !IsRootAlias;
+    }
+}