Major refactoring to make Document inspection on-demand (#579). Note that field search also have to be server side at the same time (#603). It needs to re-design REST interaction for the inspection as well asl UI side change to request inspection chunk-by-chunk.

Epic Brief: https://docs.google.com/document/d/1ZQmZD4M6llnoWzC4gEf5LxQIaCcMs2TwtQVa_hTpoLo/edit?usp=sharing