Increase no of entries per page in ;ranklist

Keep 10 as default. But allow users to manually specify no entries per page. Subject to discord embedded limit. If one cant increase the limit higher compared to 10. Then just close this.
130 users aka 13 page it too much for AC.

Start at the ;ranklist command and inspect how its Discord response is paginated and constrained by the embedded-message limit. Preserve 10 as the default, allow users to specify a larger page size, and verify that the resulting response remains within Discord's limit; if it cannot, confirm that the requested increase is not feasible.

Written by the indexing model from the issue text.