Fix Paginating, Sorting, and Searching Issues Within "Research Outputs" Tab

[aaronskiba]

Fixes the "Create paginable/research_outputs_controller.rb TODO" in #3464

Changes proposed in this PR:

• Add scope :search to ResearchOutput model: 8ecced5
  • Search query is performed by research_outputs.title (case-insensitive)
• Create app/controllers/paginable/research_outputs_controller.rb 301231c
  • This new controller fixes the following features on the /plans/:plan_id/research_outputs page:
    • The clickable pagination options (e.g. View all,1,2,Next,Last)
    • The search box (for research_outputs.title matches)
    • The clickable sorting arrows