Discuss whether the Announcements module should be marked as alpha or beta

Problem/Motivation

This is a follow-up to #3206643: Project messaging channel in core (as experimental) as it was marked as RTBC.

Quoting @alexpott on that issue:

I'm not sure if this should go in as beta or as alpha. As it stands I don't think that this module offers an API. All classes are final and marked as @internal. Things can be opened up in beta or once this module as stable as necessary. Maybe someone can open an issue to discuss this

So let's use this issue to discuss this and the possible next steps.

Reading on alpha, beta, stable: https://www.drupal.org/about/core/policies/core-change-policies/experime...

Steps to reproduce

Proposed resolution

Remaining tasks

User interface changes

API changes

Data model changes

Release notes snippet