Abstract reviewing: provide more options for customizing the reviewer track view

The filtering/sorting/abstract list customization options in the reviewer track view is a lot more limited than the manager's view.
Reviewer track view

Manager view

**Simple(?) fix**
It would be already helpful if the reviewer track view can have the same filtering/sorting/customization options as the managers view.

**Particular use cases**
It would be helpful if the reviewer track view can be made much more similar to the manager's view, to enable sorting according to scores. This will enable reviewers to impose a ranking for the abstracts in the track, if they wish.

It would also be helpful to have the extra filter for abstracts proposed for multiple tracks, as well as a filter for abstracts that were only proposed in one track.

**Ideal but probably complicated**
It would be ideal if it will be possible for managers to fully customize the customization options/columns that are available to the reviewer, and define some "default" columns.

Thanks,
Ying

No file or test is named. Start by comparing the reviewer track view with the manager view, then trace the existing filtering, sorting, and abstract-list customization entry points. Done means reviewers can use the requested score and track-proposal filters, with the intended customization behavior defined and covered by appropriate tests.

Written by the indexing model from the issue text.