Add translation support for Bulgarian (#5863)

* Enable Bulgarian for backend

* Build out initial backend translations

* Add integration for frontend

src/frontend/.linguirc

@@ -1,5 +1,6 @@
 {
     "locales": [
+        "bg",
         "cs",
         "da",
         "de",

src/frontend/src/contexts/LanguageContext.tsx

@@ -10,6 +10,7 @@ import { useLocalState } from '../states/LocalState';
 export type Locales = keyof typeof languages | 'pseudo-LOCALE';
 
 export const languages: Record<string, string> = {
+  bg: t`Bulgarian`,
   cs: t`Czech`,
   da: t`Danish`,
   de: t`German`,

src/frontend/src/locales/bg/messages.d.ts

@@ -0,0 +1,4 @@
+import { Messages } from '@lingui/core';
+          declare const messages: Messages;
+          export { messages };
+