Added helper for defining missing permissions not implemented but exist in feature exports.

## Ready State: Yes

Implementation of `hook_permission` which contains a helper code to define any missing permissions that may be exported by features but not actually implemented by any module.

## Deployment

* Merge code.
* Clear caches with `drush cc all`
* Revert any features (or all) that implement `user_permission` component. (`drush fra -y`)