Add mm_cache_clients_with_addons to cfg

cfg/multiaddonmanager/multiaddonmanager.cfg

@@ -2,3 +2,4 @@
 mm_extra_addons 				""		// The workshop IDs of extra addons, separated by commas (e.g. "3090239773,3070231528")
 mm_extra_addons_timeout			10		// How long until clients are timed out in between connects for extra addons, requires mm_extra_addons to be used
 mm_addon_mount_download			0		// Whether to download an addon upon mounting even if it's installed
+mm_cache_clients_with_addons	0		// Whether to cache clients who downloaded all addons, this will prevent reconnects on mapchange/rejoin