[REQ] Settings: Implement optional default language setting if left undefined; Set default view [basic/batch]; Dark mode

[ryehamstrawberry]

Please consider the following feature requests:

• Implement the ability for user to save a preferred default language to be used if language is otherwise left undefined;
• Add default view mode to be used on launch: basic/batch;
• Dark theme.

Thank you in advance for the time and effort you've invested in this excellent utility.