Move settings into a subfolder

[humdingerb]

There are now quite a few settings files under ~/config/settings.
I prefer to have a subfolder "Weather" in such a case. While at it, maybe also change their naming scheme to be consistent while touching it.

We could add a post-install script to the package that copies any old settings to their new location. It can be removed again after a few releases, when most users should have migrated from old versions.