make upgrading easier

[BBC-Esq]

The paths to the databases are put into the config.yaml when created. Make it so the paths are relative if possible so that if a user copies and moves the repository folder that it will still work.

Moreover, add a feature to easily upgrade from within the GUI when there's a new release, which will add/remove/update any dependencies, scripts, etc., but keep intact any databases, embedding models downloaded, etc.