Fix race condition in sending started signal from monitor

Signed-off-by: Alexandr Morozov <lk4d4math@gmail.com>
Fix race between container cleanup and inspect/ps

Signed-off-by: Alexandr Morozov <lk4d4math@gmail.com>
Fix race on state serialization

Signed-off-by: Alexandr Morozov <lk4d4math@gmail.com>
Cleanup: Make channels unbuffered

Signed-off-by: Alexandr Morozov <lk4d4math@gmail.com>