Better visual treatment of rows per page in table controls

[david-crespo]

If it's not editable, don't make it look editable. If it is editable, make it work — likely not with typing in arbitrary values but a small menu with 10, 20, 50 or something. This issue is split off from #1082.

[benjaminleonard]

Could swap to a fill instead of a stroke to make them look less like inputs:

[david-crespo]

MVP: Small thing but I think pagination is very important.