Added SMTP Collector and its client

Work in progress. This here is actually working, we will just have to sort the style how to plug this in to be the best for use.

The server here does not use authentication, but that might be implemented, too.

So:
* SMTP setup fixture (?)
* Fixture, providing `SMTPCollectorClient`

As a consequence of this getting merged will be event listener fixture using `parsetime` for handling the datetime transmission over http, too, to DRY.