Implement the feature described in https://jira.magnolia-cms.com/browse/MAGNOLIA-6664, but usable from a code based definition, including Blossom.

Summarized: When creating a definition in code - it is possible to use an "inherits" feature such that the current definition starts with all properties of the inherited definition, but can then override those values with new ones.

To be determined: actual syntax available in code to inherit a definition.