job to delete trashed ciphers nightly (#1243)

* job to delete trashed items nightly

* remove script from migration project file

* admin setting for controlling trash deleting dates

util/Migrator/DbScripts/2021-03-26_00_CipherDeletedIndex.sql

@@ -0,0 +1,36 @@
+IF OBJECT_ID('[dbo].[Cipher_DeleteDeleted]') IS NOT NULL
+BEGIN
+    DROP PROCEDURE [dbo].[Cipher_DeleteDeleted]
+END
+GO
+
+CREATE PROCEDURE [dbo].[Cipher_DeleteDeleted]
+    @DeletedDateBefore DATETIME2 (7)
+AS
+BEGIN
+    SET NOCOUNT ON
+
+    DECLARE @BatchSize INT = 100
+
+    WHILE @BatchSize > 0
+    BEGIN
+        DELETE TOP(@BatchSize)
+        FROM
+            [dbo].[Cipher]
+        WHERE
+            [DeletedDate] < @DeletedDateBefore
+
+        SET @BatchSize = @@ROWCOUNT
+    END
+END
+GO
+
+IF NOT EXISTS (
+    SELECT * FROM sys.indexes  WHERE [Name]='IX_Cipher_DeletedDate'
+    AND object_id = OBJECT_ID('[dbo].[Cipher]')
+)
+BEGIN
+    CREATE NONCLUSTERED INDEX [IX_Cipher_DeletedDate]
+        ON [dbo].[Cipher]([DeletedDate] ASC)
+END
+GO