feat(files): add possibility to set the audio quality of downloaded files

it is possible now to se audio quality of files using environment variables (QUALITY)

close #39

src/backend/.env.default

@@ -2,6 +2,7 @@ DB_PATH=./config/db.sqlite
 FE_PATH=../frontend/browser
 DOWNLOADS_PATH=./downloads
 FORMAT=mp3
+QUALITY=
 PORT=3000
 REDIS_PORT=6379
 REDIS_HOST=localhost

src/backend/src/shared/youtube.service.ts

@@ -42,6 +42,7 @@ export class YoutubeService {
         cookiesFromBrowser: this.configService.get<string>('YT_COOKIES'),
         headers: HEADERS,
         jsRuntime: 'node',
+        audioQuality: this.configService.get<string>('QUALITY'),
       },
     );
     this.logger.debug(