Python: Create error message for broker connection

[SvenO3]

Body

If the StreamPipes Python Functions want to connect to a data stream and the connection isn't successful, it waits for a connection forever without giving feedback to the user. Therefore an error message should be created after the connection couldn't be established after a given time.

StreamPipes Committer

I acknowledge that I am a maintainer/committer of the Apache StreamPipes project.