Change user status into a boolean, "active" or "is_active"

[Christopher Allan Webber]

Currently we have status being one of "active" or
'needs\_email\_verification'... we could simplify things by just
having email\_verified (which we already have) and "active" be a
boolean.

The role of active will then switch to whether or not the user is
enabled. You might set active to False if a user was abusing their
account, for instance.

The migration on this should be pretty easy... just remove
needs\_email\_verification and make all existing users active,
since currently we don't have any inactive state.

This is a bitesized task.