Restrict attribute release at compile time

Restrict the set of attributes to allowable values during metadata
import instead of at run time.
Remove redundant code
Map from OIDs to Friendly Names

The metadata import delivers OIDs, for easier specification of release
rules map (required) attributes to friendly names.
Activate mapping code
Fixed the bugs
Adjust the template

The attribute release rules now work with friendly names.
Merge branch 'use-friendly-names' into early-pruning
Adjust the template for early pruning
Add missing attribute