ZKL: add "Hide passworded", fix 'close' button not working on PM tab, some grammar fix

*Implemented https://github.com/ZeroK-RTS/Zero-K-Infrastructure/issues/149  as "Hide Passworded" and also renamed "Show Empty" to "Hide Empty" and "Show Full" to "Hide Full" because in my opinion "hide" is more consistent with the filtering mechanism of these checkboxes.

*Fix "close" menu item button not working for PM Tab

*Fix https://github.com/ZeroK-RTS/Zero-K-Infrastructure/issues/168 "Show featured map" --> "Show featured maps"