Start all required services via init-sequence

[alex-kononovich]

Currently we have to launch state-service, front-service and init-service manually via websocket, because init-service cannot be started before previous two are launched and successfully checked in.

The way init-sequence currently works does not allow to simply list services in init sequence, because while it does launch containers in sequence, but it doesn't wait for checkin message from them, so it's quite possible that required containers won't start in time for init-service to launch.

Possible fix for that could be to extend Hexfile syntax in a way that it's possible to declare a dependency of one service on another (or rather list of dependencies), and wait for dependencies to send their checkin messages before starting dependent container.