[server] commit after serializing schema
Use separate transactions for schema serialization and postcreate
scripts execution, so that the latter can rely on the schema being
persistently stored. This matters e.g. if something in a postcreate
violates a unique_together constraint, we need the constraint persisted
in order to raise a meaningful error. See #4525069.
addressbook
basket
blog
book
calendar
comment
company
email
file
folder
i18ncontent
keyword
link
mailinglist
person
tag
timeseries
vcsfile