WPB-21964: Add Wire Meetings creation endpoint

[blackheaven]

https://wearezeta.atlassian.net/browse/WPB-21964

Checklist

• Add a new entry in an appropriate subdirectory of changelog.d
• Read and follow the PR guidelines

[akshaymankar]

I haven't reviewed everything yet, I'll continue later. But already have some feedback.

[akshaymankar]

Why is this decision made outside the subsystem?

[blackheaven]

It'll force to move feature flags from galley to wire-subsystem, which is heavy, as it rely a lot on galley mechanisms, and couple wire-subsystem to galley.

[akshaymankar]

I think we should just do this kind of refactoring when we need it, if we keep waiting for explicit refactoring tickets, we'll end up making our code more complex. I'd think feature flags is not the most complex thing to move. But even if it is. we can also just create a Subsystem effect in wire-subsystems and keep the interpreter in galley, so the coupling is only via the subsytem interface. We've already done this for TeamSubsytem, for instance.

[blackheaven]

I'll create a dedicated PR, because when I have tried, it was too complex and complicated.

[akshaymankar]

We're bypassing the ConversationSubsystem business logic (I know the subsystem doesn't exist yet) here. This is dangerous. For instance, I can already tell that this would break if MLS is disabled.

[blackheaven]

Should I wait for the PR introducing it, or could we assume it is safe as long as the conversation params do not change?

[akshaymankar]

I think its not safe to assume things here, things can change tomorrow. Ideally we'd either do this refactoring now or we can also create an "incomplete" subsystem for Conversations and keep its interpreter in galley. This is how we dealt with some dependence on the TeamSubsystem.

[blackheaven]

There is an effect in libs/wire-subsystems/src/Wire/ConversationSubsystem.hs, should I add a constructor and pass it directly to the store for the moment?