Update configuration definitions to make a few different types of changes:

- Add CDDL headers to files that were missing them
- Change the syntax for some attributes whose values were supposed to be
  attribute types into "attribute-type"
- Add appropriate base values for some properties with the DN syntax
- Change a couple of descriptions that had inaccuracies or copy-and-paste typos
- Change a couple of default values to match what's defined in the config file
- Provide a couple of overrides for classes in config definitions that extend a
  parent definition (in particular, override classes for attribute syntax
  implementations)