Since we may not want to enable the identity check, it must be
togglable. This commit adds environment variable
REACT_APP_ENABLE_IGA_CHECK for toggling the check in the frontend, and
django settings variable IGA_CHECK for toggling the check in the
backend.

Andreas Ellewsen authored 3 years ago and Jonas Braathen committed 3 years ago

If a sponsor verifies a nin that is already in use by an account in
cerebrum, the guest will gain access to that account, which in turn
allows the guest to change the password of that account. This makes it
possible to abuse the guest service to steal the account of users.

A feature that checks for this problem, and helps the sponsor make a
decision on it, will be introduced in the near future. At that point
nin verification can be enabled again.

Resolves: GREG-202

Resolves: GREG-200

No need for two config variables. Use the appInst config to get the
correct theme.

This reverts commit 2d5db5b2.