feat(vm-provision): declare the guest agent per guest OS, Linux only

Follows napalm-device-types 3.0, which replaces GUEST_AGENT_PACKAGES /
GUEST_AGENT_RUNCMD with GUEST_AGENTS = {guest_os: (packages, runcmd)}.
VMware lists Linux with open-vm-tools, as before, and refuses any other
guest_os before anything is created: BSD guests on VMware are optional
for now (NetOrk/netork#801).

The NoCloud network-config moved to napalm-device-types
(`provisioning.network_config`), which Proxmox now uses as well; the seed
module's copy is gone, and the tests check that the generic one is used.

tests/test_drivers.py

@@ -94,8 +94,14 @@ class TestIdentity:
         assert callable(getattr(cls, method, None))
 
     @pytest.mark.parametrize("cls", DRIVERS)
-    def test_declares_its_guest_agent(self, cls):
-        assert cls.GUEST_AGENT_PACKAGES == ("open-vm-tools",)
+    def test_provisions_linux_guests_with_open_vm_tools(self, cls):
+        """Linux only: BSD guests on VMware are optional (NetOrk/netork#801)."""
+        assert cls.GUEST_AGENTS == {
+            "linux": (
+                ("open-vm-tools",),
+                ("systemctl enable --now open-vm-tools || systemctl enable --now vmtoolsd",),
+            ),
+        }
 
 
 class TestOptionalArgs: