Pass option to forum_pages_widget helper

The view files in forem uses `forem_pages_widget` helper to render pagination, but there is no way to pass in additional arguments. I thought adding arguments might be useful.

For instance, such need arises when using will_paginate-bootstrap to style pagination rendered by will_paginate. People need to pass `renderer: BootstrapPagination::Rails` to will_paginate helper, but currently there is no easy way to do so.