[UX] Skip already finished documents automatically

[hunnguye]

Is your feature request related to a problem? Please describe.
Our annotators reported the following issue:

• We have documents A, B, C, D.
• Document C is already marked as finished.
• When an annotator is working on document B and clicks "Next," document C (which is already finished) is loaded instead of skipping to document D.

This behavior may seem minor but becomes frustrating and time-consuming, especially with large datasets. Our context is as following:

• we load the Documents into projects in batches.
• Once annotators complete most of the workload, we load new documents into Inception.
• Documents appear to be ordered alphabetically, so when the initial workload is finished and if there are new documents ordered in between the already finished once, the above mentioned issues occur..
• This problem will become increasingly noticeable when dealing with large projects (e.g., 5,000 documents) and regularly adding new batches (e.g., 200 new documents).

Describe the solution you'd like
For annotators, don't show already finished (and in read-only mode) documents. The specific UI implementation can be subject for discussion. I think a general configuration or user specific toggle button would be handy.

Additional context
Inception Version 34.5