feat: Translate frontend/src/i18n/en.json in bg

98% of minimum 50% translated source file: 'frontend/src/i18n/en.json'
on 'bg'.

Sync of partially translated files: 
untranslated content is included with an empty translation 
or source language content depending on file format

frontend/src/i18n/bg.json

@@ -264,8 +264,8 @@
   },
   "time": {
     "days": "Дни",
-    "hours": "Hours",
-    "minutes": "Minutes",
+    "hours": "Часове",
+    "minutes": "Минути",
     "seconds": "Seconds",
     "unit": "Time Unit"
   }