Added message streams manager and model

[yardensachs]

Message Stream Manager and Model Integration:

Introduced a new MessageStreamsManager to handle all operations related to message streams. Implemented a MessageStream model that represents individual message streams.

In addition, given the comments in #214, I added new methods to handle subscription suppressions. This allows to dump, create and delete email address suppressions.

[yardensachs]

I am not sure how to use the betamax, I hope the tests I write are enough.

[Stranger6667]

Cool, I’ll try to find some time to review it :) re: betamax- at some point it will be nice to move to pytest-recording :)

[yardensachs]

i wonder who is the maintainer of pytest-recording 😅

[Z33DD]

Any progress on this?