Filter exported users to those who don't exist in AD

[steven-cd]

Split from #202 - when we export a list of users, we should be able to filter out (or at least identify) those who have already been created in AD.

This will require us to get that information somehow. We may be able to do this through Graph API calls, but we will have to identify how we get the requisite permissions. Another option would be to track who had logged into the application, which should be simple enough, but won't be completely accurate, i.e. there will be a delay between an account being created and the user logging in, and it won't capture users who never log into the webapp at all, such as normal researchers.

[tomdoel]

I've added two options which appear when you click Export User List (see screenshot):

• Export list of users without accounts
• Export list of all users

@bw-faststream @steven-cd Is that clear enough, or is there a better way of phrasing these options? I'm trying to avoid saying 'Active Directory' as the webapp is agnostic to how the users are defined in the system. I guess that only Programme Managers and System Managers would ever actually see this.

[bw-faststream]

I think that looks really clear, cheers

[tomdoel]

Fixed in #292