add an interactive test

[hwmrocker]

Add a cli that asks you for credentials and send one email.

We need this to be able to verify that sending via gmail still works.
This part will not be automated, it could be that google will block the account because of the automated behaviour.

[sameer-j]

I would like to contribute to this

[hwmrocker]

Thank you, just create an PR and I will review it :)