Replace custom socket implementation with SignalR.

Replace MSAL and custom cookie auth with Microsoft.Identity.EntityFramework
Also some UI redesign to accommodate different login experience.

Shogi.Database/Post Deployment/Scripts/PopulateLoginPlatforms.sql

@@ -1,16 +0,0 @@
-
-DECLARE @LoginPlatforms TABLE (
-	[Platform] NVARCHAR(20)
-)
-
-INSERT INTO @LoginPlatforms ([Platform])
-VALUES
-	('Guest'),
-	('Microsoft');
-
-MERGE [user].[LoginPlatform] as t
-USING @LoginPlatforms as s
-ON t.[Platform] = s.[Platform]
-WHEN NOT MATCHED THEN
-	INSERT ([Platform])
-	VALUES (s.[Platform]);