Setup json-ld boilerplate #6188
Description
Currently, the json-ld boilderplate (namespaces, type, etc) are created in the user_metadata.json file written by django. When the landing-page begins writing to this file directly, there boilderplate will no longer be present in the resulting json-ld files.
When writing the json-ld files, ensure that the json-ld boilerplate is present.