translate app into Korean / 앱을 한국어로 번역하다

[0xadada]

Expected Behavior

Korean speakers can use the application in the Korean language.

Task

All translations are located in https://github.com/mirai-audio/mir/tree/master/app/locales, with directory for each translation language.

These should be added under a new ko directory in app/locales.

Use English as the source for translations, as it contains a complete list of up-to-date strings.