Unify "Save" and "Close" buttons in Settings

[peterzimon]

DES-27

There are two patterns used in settings modals for action buttons:

1. [Cancel] and [Save & close] (sometimes it's [Cancel] and [OK], inconsistently) — example: Staff details, Tier details, Navigation, Recommendation
2. [Close] and [Save] — example: Design settings, Portal, Newsletter details etc.

This is confusing and leaves people confused and uncertain about what's going to happen in one or the other case.