Update playlist link validation and info text

Standardized playlist link validation messages across all language files and code, removing specific references to Spotify and YouTube. Updated README and help view to reflect broader platform support and clarified instructions. Removed unused YouTube regex and related thumbnail logic from objects.py.

voicelink/ipc/methods.py

@@ -433,7 +433,7 @@ async def updatePlaylist(bot: commands.Bot, data: Dict) -> Dict:
                 return {
                     "op": "updatePlaylist",
                     "status": "error",
-                    "msg": f"Please enter a valid link or public spotify or youtube playlist link.",
+                    "msg": f"Please enter a valid link or public playlist link.",
                     "field": "playlistUrl",
                     "userId": str(user_id)
                 }