Previously, we set restrict_to_domain and invite_required differently
depending on whether we were setting up a community or a corporate
realm. Setting restrict_to_domain requires validation on the domain of the
user's email, which is messy in the web realm creation flow, since we
validate the user's email before knowing whether the user intends to set up
a corporate or community realm. The simplest solution is to have the realm
creation flow impose as few restrictions as possible (community defaults),
and then worry about restrict_to_domain etc. after the user is already in.
We set the test suite to explictly use the old defaults, since several of
the tests depend on the old defaults.
This commit adds a database migration.