PRD-5184 - Metadata system clean up to reduce the complexity of the parsing process. A bunch of pseudo-builders help to collect properties. A set of new validation tests uncovered some missing/invalid metadata in the process.
PRD-5184 - Updated the UI to handle the new maturity level. As a side-effect of the clean-up, we now also support mat-levels on attributes, styles and properties, although that is not used anywhere.
PRD-5184 - Make the maturity level default configurable via the external config. This way EE edition can limit the feature set to the supported set.
Merge pull request #536 from tmorgner/PRD-5184

PRD-5184 - Transform "experimental" flag into Maturity-Level indicators