*8710* PKP-lib changes for workflow tabs
*8710* introduce WorkflowStageDAO, refactor for index op
*8710* move participants grid to tabs
*8710* use static methods, improve readability of workflow stage methods
*8710* use static workflow stage dao methods
*8710* add check for review round
*8710* use static methods, remove old code, general improvements
*8710* remove participants grid from submission header template
Merge pull request #112 from jnugent/8710-prototype

*8710* convert workflow stage bar into tabs