memory leak fixes

[milyin]

Fixes memory leaks due to:

• cyclic reference Runtime <- Network '<- Tables <-TableLock <- Router <- RuntimeState <- Runtime
• captured sender end of channel by receiver task, which should end when all senders are gone in TransportManager::new()
• cyclic reference Runtime <- RuntimeTransportEventHandler <- TransportManager <- RuntimeState <- Runtime

To do:

• fix cyclic reference to Session from admin space handler in Session::init
• fix (or decide to ignore, to be ivestigated) leak due to not waiting to end of all threads stated by TransportExecutor::new (5a8df0f)

[fuzzypixelz]

@milyin Please change your pull request's base branch to main (new default branch). And rebase your branch against main as it is missing a status check necessary to merge this pull request but which is only available on main.