Having blurRegion to identify if a decoration supports blur or not instead of the metadata-json way has the following benefits:

- decorations can now provide both blur or not based on user preference
- theme engines such as Aurorae do not have to enforce blur or not to their themes and they can support blur enabled and disabled themes at the same time if they want to
- blurRegion is empty by default so the Korners bug will be fixed for all solid aurorae themes. Breeze and Oxygen have set **blur:false** so nothing changes for them.
- all aurorae themes that do not require blur will free up system resources by default