Upgrade Kotlin version, remove some sources of lag

[hopskipnfall]

Several sources of lag removed:

• Switch to using Timer instead of spinning up a coroutine with a delay() to avoid counting towards coroutine parallelism

• Bring back Channels for more optimal message handling

• Properly close both the KailleraUserImpl and V086Controller coroutines which were being left before

• Fix a race condition where V086Controller.close() was not being called

• Stop creating a new SelectorManager every time. Apparently the constructor spins up a new long-running coroutine every time.

• Fix a bug where freed ports were not being made available again.

There is some lag when a user logs out of the server, I'm not sure what causes this yet.