Investigate whether setting a proxy on iOS is enough

[baltpeter]

Compare #19. I haven't stumbled across anything that suggests a similar problem on iOS, but we should check nonetheless.

[baltpeter]

The results from a cursory search are inconclusive: A question from 2011 claims the situation is the same as on Android, but the only answer disagrees without citing any sources. Meanwhile, it does at least appear to be possible for apps to override the proxy they're using (https://stackoverflow.com/questions/16847858/ios-any-body-knows-how-to-add-a-proxy-to-nsurlrequest, https://developer.apple.com/documentation/foundation/nsurlsessionconfiguration/1411499-connectionproxydictionary).

We'll have to do some experiments.

[baltpeter]

@zner0L notes in tweaselORG/appstraction#42:

Also, I looked into WireGuard on iOS for a moment and they seem to support VPNs on cellular as well, so if we want to enable WireGuard on iOS we could support cellular, too.

[zner0L]

iOS supports per-app-VPNs, but only if the apps are deployed via a MDM: https://support.apple.com/de-en/guide/deployment/depae3d361d0/web#dep9613c6491