Added Sql project with database schema. Added SqlServer repositories for Site, Folder, and User (Cipher still TODO). Switched DI in Startup to SqlServer repos.

src/Sql/dbo/Tables/User.sql

@@ -0,0 +1,20 @@
+CREATE TABLE [dbo].[User] (
+    [Id]                 UNIQUEIDENTIFIER NOT NULL,
+    [Name]               NVARCHAR (50)    NULL,
+    [Email]              NVARCHAR (50)    NOT NULL,
+    [MasterPassword]     NVARCHAR (300)   NOT NULL,
+    [MasterPasswordHint] NVARCHAR (50)    NULL,
+    [Culture]            NVARCHAR (10)    NOT NULL,
+    [SecurityStamp]      NVARCHAR (50)    NOT NULL,
+    [TwoFactorEnabled]   BIT              NOT NULL,
+    [TwoFactorProvider]  TINYINT          NULL,
+    [AuthenticatorKey]   NVARCHAR (50)    NULL,
+    [CreationDate]       DATETIME2 (7)    NOT NULL,
+    CONSTRAINT [PK_User] PRIMARY KEY CLUSTERED ([Id] ASC)
+);
+
+
+GO
+CREATE NONCLUSTERED INDEX [IX_User_Email]
+    ON [dbo].[User]([Email] ASC);
+