TODO: add settings option to use locale default hour hour cycle

[ehanahamed]

Right now, when the hour cycle (24 vs 12 hour time) setting is unset, it will use the browser locale's default setting. In settings, users can choose to override their locale's/language's opinion and select 24h or 12h time. There should be another option in settings to go back to using they're locale's default (which would just make it unset)