In previous commits, we updated the realm creation flow to show
the realm name, type and subdomain fields in the first form
when asking for the email of the user. This commit updates the
user registration form to show the already filled realm details
as non-editable text and there is also a button to edit the
realm details before registration.
We also update the sub-heading for user registration form as
mentioned in the issue.
Fixes part of #24307.
We now show inputs for realm details like name, type and URL
in the create_realm.html template opened for "/new" url and
these information will be stored in PreregistrationRealm
objects in further commits.
We add a new class RealmDetailsForm in forms.py for this
such that it is used as a base class for RealmCreationForm
and we define RealmDetailsForm such that we can use it as
a subclass for RegistrationForm as well to avoid duplication.
This commit updates the ID for form element in create_realm.html
to "create_realm" as we would need to update the error handling
for this page in further commits and we do not want to break it
for other forms using "send_confirm" as ID.