Pagination - Add custom 'perPage' value to array 'perPageValues'

[MrYamous]

If I choose a custom perPage, but if this value isn't in perPageValues, my custom value isn't proposed in select list and I feel like this is a confusing behavior
I suggest to automatically add the perPage to perPageValues array to avoid this

I think I can work on a PR for this, but I open a discussion for advices and as a reminder for myself

In this image the table can show up to 20 lines, but 20 is not a valid perPageValues then 10 is displayed in select but more than 10 lines are displayed

[MrYamous]

Resolved by #1999