Migrate localizations to a purpose-built internationalization system

Right now, all localizations are partly hard-coded into the few commands that support some level of localized text. Switching to an internationalized approach would allow us to completely overhaul localizations as a whole and introduce server-specific locale settings, as well as make adding localizations much simpler by leveraging the long-standing tool base.

• Establish a localization system.
• Establish localization system usage inside commands.
• Migrate existing texts into the localization system.
  • Migrate all hard-coded English strings to the (default) eng-US locale.
    Note: Administrative 'owner' commands should be left alone.
  • Migrate the French strings from constants.py to the fra-FR locale.
  • Migrate the German strings from constants.py to the deu-DE locale.
• Expand the existing locales to encompass all features.
  • Complete the fra-CA (French Canadian) locale
  • Complete the deu (German) locale
• Expand the set of localizations available to include all locales supported by Splatoon.
  • Establish the ces (Czech) locale
  • Establish the dan (Danish) locale
  • Establish the fra-FR locale
  • Establish the eng-GB (British English) locale
    (We can do better than NoE's Splatoon localization, right?)
  • Establish the hun (Hungarian) locale
  • Establish the ita (Italian) locale
  • Establish the jpn (Japanese) and jpn-Hrkt (Japanese, kana-only) locales.
    (Very important locale for Denwa-Boto!)
  • Establish the nld (Dutch) locale
  • Establish the nor (Norwegian) locale
  • Establish the pol (Polish) locale
  • Establish the por (Portuguese) locale
  • Establish the por-BR (Brazilian Portuguese) locale
  • Establish the spa-ES (Castilian Spanish) locale
  • Establish the spa-MX (Mexican Spanish) locale…complete with the cringe-inducing overuse of urban slang!
    Note: Technically this would be spa-419 (Spanish as used in the Latin Americas) per standards.
  • Establish the zh-Hant and zh-Hans locales.
    Note: zh does not represent a language as en or ja do; it's actually a written language for common communication across cultural boundaries (similar to Esperanto and Interlingua, among others). If there is any localized audio, cmn-Hant/cmn-Hans (Mandarin), yue-HK (Hong Kong Cantonese), and nan-TW (Taiwanese Hokkien) MUST be used as locales instead.
  • Establish the rus (Russian) locale
• Establish a system to ease translation efforts for the localization team.
• Establish some kind of method for end-users to potentially assist with translation efforts.