Revert "Make preferences INI path NOT be configurable"

This reverts commit 219869607dab6b9fe9d7eec5a9ae82af5dfa23e9.
Revert "Make preferences INI path NOT be configurable"

This reverts commit f2693613d1b9e169b3f7249fd71800fb5981a9db.
lib: Assume relative path for Config::resolvePath()
Config: Hard-code path to preferences INI files
Config: Remove path to preferences INI files setting
Bootstrap: Only replace config dir with its canonicalised absolute pathname when the dir exists