[Docs]: Update references to "Page List" and "Crawl URL(s)"

### Description

The workflow user guide (`/user-guide/workflow-setup/`) currently contains outdated references to "Crawl URL(s)" (now "Page URL(s)") and "Page List" (now "Page Crawl" or "List of Pages") and should be updated.

### Context

Per discussion in https://github.com/webrecorder/browsertrix/pull/2803, we may want to revisit (or better document our omission of) "seed". (cc @tw4l)