rm_attrs: Fix for parameters with whitespace
hpkg format: Generalize user/global settings file attributes

* For all identifiers: Rename global settings file to global writable
  file. We want to use the respective attribute also for other writable
  files, not only settings files.
* User settings file/global writable file info/attribute: Add
  isDirectory property/child attribute. This allows declaring global/
  user settings directories associated with the package.