Add authentication window

[SilverBut]

It is possible to use the client-side cert to auth client, and it is also necessary to set up a split config panel for credential management, so we can add some other auth type like username-password or username-TOTP in the future.

So I will add another panel called "Auth Management", which can be used to add a credential pair with a unique name. And add a drop-down menu in the server edit/add box for select one from the previous mentioned panel.

[NeatMonster]

Once something like what I mentioned is implemented, a registration and authentication system will be the next logical step.