Only static rendition definitions can be contributed to the Rendition Service.
We need a way to have dynamic rendition definitions based on a document (for instance, for Video or Picture documents, expose what is stored in the schema as renditions).
Add a new extension point renditionDefinitionProviders to contribute class extending RenditionDefinitionProvider.
RenditionDefinitionProvider exposes only one method:
Rendition definitions and rendition definition providers contributions should be able to be filtered through standard filters.