We should create a new mixin type for deprecating JCR node similar to what we have for YAML.
- We need a way to migrate apps from JCR to YAML but allow time for people to move their customizations.
- Allow a way for the definitions app to detect and warn about decorations being applied to deprecated JCR configuration.
- Be able to change the UI of deprecated configuration to distinguish it from other currently used configuration. This way users can easily see if a configuration is being used or not.