No other platform account login support

[miaulightouch]

Although there's experimental non-mbga account support, but it's not official supported.
user can't run tutorial via MasterVyrn, but it seems fine for common gameplay?

I wouldn't implement this myself, I would continue using my mbga account.

ref: b6e3f75

[miaulightouch]

non-mbga account is now unsupported again, code base is changed a lot,

[miaulightouch]

Now we has experimental DMM login, again. ca6cd30