Per Account mailing

[Wunderharke]

Hi guys,

since login is only working with cookies right now, I want to implement some file drop for my users to update their cookies if needed.
I don't know how to realize this yet, however it will be necessary that users will get notified.
For this would suggest sending a mail either to users Epic mail address or to add some new config attribute to specify a notification mail address per account when login fails.
This way, users would know it's time to update their cookie again.

I don't know how mailing is handle right now and don't use TypeScript regularly, but with some help I might be able to suppose a merge request myself.

[Wunderharke]

I just saw #101 this might be an incremental addition but account.email is available within that function already.
Might be worth considering a boolean for deciding whether sending to account.email or this.emailConfig.emailRecipientAddress.

[claabs]

Added in v4: https://github.com/claabs/epicgames-freegames-node/releases/tag/v4.0.0