This reverts the temporary fix done in commit
46f4e58782 and replaced it with the fix that
non-admins should be able to see a dropdown to select a non-admin type of
invited user i.e. normal member or guest user.
Since we have already added the `invite_as` field to models, we can now
replace usage of `invite_as_admin` properly with its equivalent `invite_as
== PreregistrationUser.INVITE_AS['REALM_ADMIN']`.
Hence, also removed now redundant `invite_as`.
These must refer to the id of an existing form control; id_username
doesn’t exist and streams_to_add isn’t a form control.
Signed-off-by: Anders Kaseorg <andersk@mit.edu>
This should make it easier to find the templates that are actually
part of the core webapp, instead of having them all mixed together
with the portico pages.