Config location on macOS should not be ~/Library/Preferences

Our use of ~/Library/Preferences as the config location seems to be incorrect:

https://developer.apple.com/library/archive/documentation/FileManagement/Conceptual/FileSystemProgrammingGuide/FileSystemOverview/FileSystemOverview.html

Preferences. This directory contains app-specific preference files. You should not create files in this directory yourself. Instead, use the NSUserDefaults class or CFPreferences API to get and set preference values for your app.

The more appropriate location is  ~/Library/Application Support:

Use this directory to store all app data files except those associated with the user’s documents. For example, you might use this directory to store app-created data files, configuration files, templates, or other fixed or modifiable resources that are managed by the app. An app might use this directory to store a modifiable copy of resources contained initially in the app’s bundle. A game might use this directory to store new levels purchased by the user and downloaded from a server. (emph mine)

See also discussion in https://github.com/dirs-dev/directories-rs/issues/62