Include local users in UserListAPIView return data?

[mikkonie]

Currently, the user list REST API view omits users in SYSTEM_USER_GROUP unless requested by a superuser.

This kind of makes sense if not allowing local users, as in this case the group only contains e.g. script users which should not be interesting to most users.

However, local users also get added to the group. This means that on a server using local users instead of external auth, regular users might end up seeing an empty user list. That is not intentional.

TBD: The proper way to handle this? Options include, in the ascending order of effort required:

1. Simply omit the limitation and display all users regardless of the requester
2. Show system users if PROJECTROLES_ALLOW_LOCAL_USERS==True
3. Differentiate local human users and script users by different groups, only hide script users

Right now I'm thinking of going with option 1, but I'll think about it. This will require bumping up the projectroles API version to v2.0 and introducing backwards compatibility, of course.

Comments are welcome.