Add support for overriding strings

For the sake of localization, we should let consumers easily override any user-facing strings. For now, I think these are the only strings that need to be localized:

"No data available" -> when no rows are loaded
"Page {{X}} of {{Y}}" -> in the pagination footer
"{{X}} items per page" -> in the pagination footer
"Clear" -> on the button that appears after you manually filter