separate config and messages DB

Presently messages and configuration are all in the same sqlite DB file.

It would be better if messages and configuration were in separate DB files this way one could have the configuration database backed up/restored easily without having to maintain a backup of a potentially large set of messages. This would also allow one to separate where each of these are stored and mounted in the docker container. In particular, this would be good to be able to store data (messages, images etc) in one location and configuration in another (a dropbox mount for example)