Fixes https://github.com/webrecorder/browsertrix/issues/1743
On the backend, support adding user to new org and improved error
messaging:
- if user exists is not part of the org to be added to, add user to the
registration org, return 201
- if user is already part of the org, return 400 with
'user_already_is_org_member' error
- if user is not being added to a new org but already exists, return
'user_already_exists'
frontend:
- if user user same password, they will just be logged in and added to
registration org (same as before)
- if user uses wrong password, show alert message
- handle both user_already_is_org_member and user_already_registered
with alert message and link to log-in page.
note: this means existing user is added to the registration org even if
they provide wrong password, but they won't be able
to login until they use correct password/reset/etc...
b061a39d5f