adding variable mail.from variable for java mail (suggestion)

Hello everyone,

In the course of creating a deployment in our environment, I noticed that the java mail client receives the user and the password, but unfortunately not the FROM address for the mail header.

This leads to an error in our setup, because in addition to the mandatory login, the FROM address must match the logging account.

I have experimented a little and the following configuration is successful:

```
# Authentication settings for the SMTP server
mail.smtp.auth=true
mail.from=< associated from address >
mail.user=< user to from address >
mail.x.password=< password to user >
```
It would be great if this were included as standard in the aktin.properties.

Best regards