cleanup and refactor page list rendering to use partial
link_to_name takes the avatar_id - not the user one

We might want to add some caching here later because fetching the avatar_id kind of defeats the purpose of link_to_name
page.owner and page.updated_by can be nil.
Merge pull request #78 from Crabgrass/bugfix/4341-fix-avatars-in-page-list

Bugfix/4341 fix avatars in page list