Added offset to 'list' method on resources.
Added "offset" and "limit" fields to the response.
Removed "next_page_token" and "next_link" fields that were not being used.
Filters out "show", "index" and "destroy" methods from discovery document generation because they are
redundant with "get", "list" and "delete".
* Added support for offset and limit query parameters (?limit=x&offset=y) to workbench index pages.
* Created _paging partial for rendering forward/backward/jump to page N
* Added paging to generic index page, index pages for collections, pipeline instances, pipeline templates, groups.
Added "Displaying X of Y out of Z"
Improved links to adjacent pages
Merge remote-tracking branch 'origin/master' into 2075-workbench-paging

Conflicts:
	services/api/app/controllers/arvados/v1/schema_controller.rb