Merge logs of app and ldk in same files, in chrono order #365
Description
Should help troubleshoot PROD bugs, best to do this before 1st release.
For impl details see how bitkit-android uses LdkLogWriter in LightningService and also check the log writer's impl details.
Also ideally we would use the same logging format in both apps;
Android already tried to copy LDK-node's logging format IIRC, so that could be used to ajust styling for iOS.