Move some user defaults key to respective framework

Initially I wanted all keys in a single header file but to avoid circular dependencies then this header would need to be in a framework that doesn’t depend on anything else, and the main benefit was only to have a single place to look for which keys exist, but now that we consistently prefix settings keys with ‘kUserDefaults’ then it’s easy to extract all keys via search.
Support disabling “keep bundles updated”

We still update the sources because the user may manually install bundles, and in this case he should install from a recent bundle index.