Next stage NHS ID development

[rebkwok]

Initial POC (#1) is complete; login with NHS Identity's OIDC flow and test user credentials on the simple OIDC realm works. The next stage is to progress to testing on the dev Healthcare realm, which requires authentication via smartcard or alternative
see Ways to authenticate

The above link is not entirely clear, but most of the methods require an N3 connection. The smartcard plugin is a custom one that needs to be provided by NHS ID, and also required the N3 connection. The method that will probably work for us for testing is a windows device + hardware key.