* fix: use fs/promises for settings
This PR switches from synchronous operations with the 'fs' module to asynchronous operations with
the 'fs/promises' module. It also corrects a small error with hostname migration.
* fix: add missing merge function of default and current config
* refactor: add more logs to migration
* feat(servarr): auto fill base url when testing service if missing
This will fill the base URL of the *arr service only if it's missing and the base URL hasn't been
provided beforehand
* fix(servarr): replace redundant check
* fix(servarr): suggested changes