3.1: New translation settings & global keyboard shortcuts

New source language setting on a per song basis: Lyric Fever remembers if you have set a specific override. Pick this if a specifci song's source language could not properly be detected.

New target language setting on an all-song basis: Lyric Fever remembers what language you want to translate to. The default behavior is to try to translate to the system language.

New chinese specific behavior: can convert between Simplified, Traditional (Neutral), Traditional (HK), traditional (taiwan)

New global keyboard shortcuts menu:

new traditional chinese translation by @ARui-tw