Draft: use abstract namespace socket

This replaces the unix socket file /tmp/monado_comp_ipc with an abstract namespace socket not backed by a file but using a global name \0monado_comp_ipc. It has the advantage that the kernel cleans up this socket whenever the application (monado-service) exits or crashes for any reason.

This is a very simple workaround for the current requirement of deleting /tmp/monado_comp_ipc when seeing the message Could not bind socket to path /tmp/monado_comp_ipc: is the service running already?.