packaging: split vgpu perception into separate libvgpu-perception0 + -dev packages

- the vmsig package no longer ships the gpu lib; it is a Sensor lib for the control, not the daemon
- vgpu-perception gets SOVERSION; runtime (libvgpu-perception0) and dev (-dev) packages, like the vmie split
- per-component install + a 3-package make deb; fix a stale comment (the windows producer is in-tree)

packaging/deb/vmsig/control.in

@@ -0,0 +1,13 @@
+Package: vmsig
+Version: @VERSION@
+Section: admin
+Priority: optional
+Architecture: amd64
+Depends: @DEPENDS@
+Maintainer: @MAINTAINER@
+Description: VM signaling coherence daemon
+ vmsig serves a unix-socket control plane over the signaling layer for the VMs it
+ discovers: lifecycle/state, coherent guest address-space context handoff, and arbitrated
+ input and memory-write actuation. Ships the daemon (vmsigd), the signaling library, and a
+ systemd unit. Configured via /etc/vmsig/vmsigd.conf. The host-side vgpu perception library
+ is a separate package (libvgpu-perception).