Reuse admin search component in other sections

There are some sections where we are not reusing it:

* The budget investments search is completely different, so this
  component isn't appropriate there
* Booth assignment and officers are slightly different, and I'm not
  entirely sure it's safe to refactor these cases

app/controllers/admin/poll/questions_controller.rb

@@ -7,8 +7,6 @@ class Admin::Poll::QuestionsController < Admin::Poll::BaseController
 
   def index
     @polls = Poll.not_budget
-    @search = search_params[:search]
-
     @questions = @questions.search(search_params).page(params[:page]).order("created_at DESC")
 
     @proposals = Proposal.successful.sort_by_confidence_score