Effects should be dumb, without any logic

[janherich]

Works towards status-im/swarms#74 idea

Summary:

Coeffects/effects should be simple and not contain any logic other then implementation details about how the side effects are actually translated (whether it's direct call, queueing for later processing, batching, etc.) so they can be re-used to maximal extent.

Having actual application logic is them is bad because:

1. They are less re-usable
2. Hard to test

Also, I removed :message-overhead field in chat realm/app-db entity and every logic associated with it. It looks like some relict from older code, we were setting it, but it was never actually red.

As another thing, it fixes #3249

Testing notes (optional):

Chat regression testing

status: ready

[goranjovic]

Any reason why you changed this to an unqualified keyword?

[janherich]

Because implicitly qualified keywords are exceptionally bad idea when they are used outside the namespace where they were defined (and that was the case).
So it was ::delete-messages keyword defined in status-im.chat.handlers ns, and grep for for ::delete-messages revealed that the keyword is used only there - so far so good, but then I realised, then some other namespace status-im.ui.screens.group.chat-settings.events is actually importing the former namespace and refering to that keyword as ::chat-events/delete-messages....

[goranjovic]

Good catch! We should add this to guidelines somewhere, just to be aware if we see the same conundrum again

[yenda]

I would move these events in the data-store with data-store.message namespace though

[janherich]

@yenda Correct, that's what I ultimately want to do once all data-store.message and data-store.chat side effect functions are called only from co-effects/effects and basically define the co-effects/effects there instead of those side-effect functions (that way, keeping both data-store.ENTITY and data-store.realm.ENTITY namespaces will finally have some purpose, public co-effects/effects in the former ns and db accessors in the later)

[asemiankevich]

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Branch: PR-3228
Android: https://i.diawi.com/UdF6Cd
iOS: https://i.diawi.com/FwrGvR