feat: licenses, a hypervisor's hosts and the package proxy as facts (4.14.0)

Drivers report facts and the application decides what is a warning
(docs/STRUCTURE.md, NetOrk/netork#1111). Three facts drivers so far
only reported as warning codes get contracts:

- LicenseMixin.get_licenses(): licenses and subscriptions with their
  status (a Proxmox subscription, a VMware edition, a BMC license a
  feature needs).
- HypervisorDriver.get_hypervisor_hosts(): each host connected, in
  maintenance, with configuration issues, under a central manager.
- PackageProxyMixin.get_package_proxy(): the proxy apt fetches through.

All declared only.

pyproject.toml

@@ -4,7 +4,7 @@ build-backend = "setuptools.build_meta"
 
 [project]
 name = "napalm-device-types"
-version = "4.13.0"
+version = "4.14.0"
 description = "Abstract device-type base classes for NAPALM drivers"
 readme = "README.md"
 requires-python = ">=3.10"