Create `horustctl` for controlling horust via cli

[FedericoPonzi]

As a normal User,

• I can use horustctl to check the status of the services
• I can use horustctl to start and stop the services which are being run as myself
• After I've update a service, I can use horustctl to tell horust to pickup the new service.

As a root User,

• I can use horustctl to check status of the services, and start / stop all of them.

[bogusfocused]

I suggest using fifodir as a communication bus as described in https://skarnet.org/software/s6/fifodir.html

[vjeson]

When can this feature be implemented? These functionalities are very useful. When I add multiple services, I need to restart one of them, but currently there is no way to do it, I can only restart all services.

[FedericoPonzi]

I will try to spend some time on it this week.