DevTools: Refactor AdvancedSearchController-related code

This patch:
  - Extracts SearchConfig.js and FileBasedSearchResultsPane.js
  - Moves file-query matching into SearchConfig
  - Decouples SearchScope from SearchResultsPane

R=pfeldman, vsevik

Review URL: https://codereview.chromium.org/225633003

git-svn-id: svn://svn.chromium.org/blink/trunk@171057 bbb929c8-8fbe-4397-9dbb-9b2b20218538