Story 488: Add pageimages to search results (beta)

Also includes new styling in stable for search error

On search results list add page images to the left of search
results in beta.
Update stable to use same markup.

Associated changes:
* Remove lots of dead code
* Rename mw-mf-watchlist-results class to more generic .page-list
and apply to nearby and watchlist views
* Make search results use articleList template

Change-Id: I938c8cf9448ed510bbf88c7d042193dcd35a7d8e
Merge "Story 488: Add pageimages to search results (beta)"