Core: use shlex splitting instead of whitespace splitting for client and server commands (#4011)

MultiServer.py

@@ -15,6 +15,7 @@ import math
 import operator
 import pickle
 import random
+import shlex
 import threading
 import time
 import typing
@@ -1152,7 +1153,7 @@ class CommandProcessor(metaclass=CommandMeta):
         if not raw:
             return
         try:
-            command = raw.split()
+            command = shlex.split(raw, comments=False)
             basecommand = command[0]
             if basecommand[0] == self.marker:
                 method = self.commands.get(basecommand[1:].lower(), None)