Rename SMW_setup.php to setupStore.php

- The script has several issues but are not addressed in this PR
- Deprecate `SMW_setup.php`
- Add `SetupStoreMaintenanceRegressionTest`
Not a real issue, but I'd also omit these. These tags are only helpful in public interfaces. This class is not (ie we do not want extensions to depend on this class or know about it)