Added apex resync script

BUG: Some devices having issues with mounted apex while flashing some packages.
 TEST: Added a device specific script in the device tree, which deloaded the apex, which are not needed and its fine.

 Example script: https://gist.github.com/AndroiableDroid/cf5a04f80b6326c759a59be5d828434e

Change-Id: I5c89dcd92871fec63c6a875c1a47eb8145ba71fa
Signed-off-by: Mohd Faraz <androiabledroid@gmail.com>

partitionmanager.cpp

@@ -301,6 +301,7 @@ int TWPartitionManager::Process_Fstab(string Fstab_Filename, bool Display_Error)
 			} else {
 				property_set("twrp.apex.loaded", "true");
 			}
+			TWFunc::check_and_run_script("/sbin/resyncapex.sh", "apex");
 		}
 	}
 #ifndef USE_VENDOR_LIBS