feat: Add ConfigSynced event

[iequidoo]

Add an event for a case if a multi-device synced config value changed. Maybe the app needs to refresh smth on such an event. For uniformity it is emitted on the source device too. The value is omitted, otherwise it would be logged which might not be good for privacy.

Needed for deltachat/deltachat-desktop#3624

[Simon-Laux]

still needs cffi and jsonrpc

[iequidoo]

We can drop the SelfavatarChanged event soon then. Note that it is also emitted on the source device too, it's easier to process all these events than add an extra code to refresh UI/caches in the app.

[Simon-Laux]

We can drop the SelfavatarChanged event soon then

rather mark it first as deprecated and we remove it later unless it is not released yet.

[iequidoo]

I don't like rustfmt so frequently reformatting code and messing up git history, but this time it reduced the number of LOCs, so let it be

[link2xt]

If rustfmt is a problem just put cargo fmt into separate commit at the end of the patch stack so it can be easily removed and recreated if needed.

[r10s]

the new event is missing in deltachat.h - even though it is not used currently, cffi is the still most complete and accurate documentation and we should maintain it for completeness. also, might be that it will become handy :)

[iequidoo]

If rustfmt is a problem just put cargo fmt into separate commit at the end of the patch stack so it can be easily removed and recreated if needed.

It's already the last commit in the patchset.

the new event is missing in deltachat.h - even though it is not used currently, cffi is the still most complete and accurate documentation and we should maintain it for completeness. also, might be that it will become handy :)

Thanks, forgot to add it, done.

[iequidoo]

Merging this, it's in fact a one-line change wrt the program logic