Include playbook url into mail

[danielgoncharov]

[danielgoncharov]

I am a bit hesitant to modify the signature of SendNotification, as it is used not only in the AddUnknownClientId case, thus, I keep it as is and just extracted the the logic to the separate method.

@JHK please have a look whenever you have time

[danielgoncharov]

@JHK please have another look whenever you have time

[jojahner]

@danielgoncharov is this still something that you would like to get in?

[danielgoncharov]

Lets close it, we will deprecate the whole thing anyway soon