VE-472: add file detail pages for cart items.
VE-472: create WikiaMediaPageWidget; refactor and cleanup logic in dialog.
VE-472: more selective selectors for WikiaMediaInsertDialog.
VE-472: initial layout for media page.
VE-472: add file extension next to title (for photos).
Merge branch 've-sprint-5' into VE-472

Conflicts:
	extensions/VisualEditor/wikia/modules/ve/ui/dialogs/ve.ui.WikiaMediaInsertDialog.js
	extensions/VisualEditor/wikia/modules/ve/ui/styles/ve.ui.WikiaMediaInsertDialog.scss
Merge branch 'VE-472' into ve-sprint-5

Conflicts:
	extensions/VisualEditor/wikia/modules/ve/ui/styles/ve.ui.WikiaMediaInsertDialog.scss