SMTP Server Configuration window bugs and enhancements

[artspb]

This is all about SMTP Server Configuration window.

1. Port input should have fixed size that enough for 5-digit port number.
2. Port number should not be formatted. For example for now port 2500 looks like this: "2 500".
3. Validation of port value should be performed.
4. Username and Password inputs should be disabled when windows was opened. For now it's disabled only when you chose Anonymous mode manually.
5. Password input should mask letters (*****).