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

80% 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

@@ -211,7 +211,7 @@
       "delete": "Изтриване на файлове и директорий",
       "download": "Сваляне",
       "execute": "Изпълни команди",
-      "modify": "Edit files",
+      "modify": "Редактирай файлове",
       "rename": "Rename or move files and directories",
       "share": "Share files"
     },