refactor(ratelimit): Return Duration from Ratelimit functions

[iequidoo]

[iequidoo]

These jobs:

Rust tests (macos-latest, 1.82.0)

for some reason are in the Expected — Waiting for status to be reported state, in dependabot PRs too.

[r10s]

to me, it was clear before this PR what gets to https://webxdc.org/docs/spec/sendUpdate.html#messaging-layer-limits-for-sendupdate and less now.

so, not sure if the refactoring is worth effort, discussion and possible bugs. the value is anyway not used inside rust.

if we want that change, i agree, we need to add an explicit test that cffi / jsonrpc really gets the thing as type int with value 20000

from reading the PR this is not clear to me

[iequidoo]

So, now the changes are limited to the deltachat-ratelimit. I only renamed WebxdcInfo::send_update_interval to send_update_interval_ms in addition because it's not related to JS land directly