Implemented distribution list I/O based on the distlists file the old approach had been using.

- load and save code is basically copy&paste from the respective methods of the old DistributionListManager.

- in ResourceFile::save() I changed form the direct call to Format::saveAll to the already existing saveToFile() method so the distribution lists are saved as well

- use the already exisiting dir watcher to also watch the distslists file