[postcreate] properly set is_instance_of for bootstrap entities Entities created before CWEType itself need the is/is_instance_of relations created later. We were actually only inserting "is". Closes #7656606.

addressbook
basket
blog
book
calendar
comment
company
email
file
folder
i18ncontent
keyword
link
mailinglist
person
tag
timeseries
vcsfile