publication_count() is slow

[nics]

publication_count() in index_user.fix slows makes indexing the user table 20 to 200 times slower. It should be rewritten or turned into an asynchronous job.

[vpeil]

Basically, this feature was intended for batch jobs. The described behaviour was not intended. So how to distinguish that as they use the same code base.

[nics]

If we move this to the model, we can do: publications->add($stream, skip_before_add => ['publication_count'])

[nics]

Turning these fix steps into hooks is generally preferred probably, as they make turning features on and off possible.