feat!: report hosts and licenses as facts, not warnings (0.2.0)

get_device_warnings is gone; netOrk names the warnings from facts
(netOrk #1111). get_hypervisor_hosts() reports each host's connection
state, maintenance mode, configuration issues and managing vCenter;
get_licenses() the assigned licenses with the edition key as edition,
never the key itself.

The reach stays: the ESXi driver reports connected as None (a
disconnected host could not have answered), and managed_by only for a
host it reached directly. parse/warnings.py is replaced by
parse/hosts.py and parse/licenses.py.

tests/test_vcsim.py

@@ -50,7 +50,8 @@ def test_esxi_reads(esxi):
     assert esxi.get_vm_storage_pools()
     assert esxi.get_virtual_networks()
     assert "cpu" in esxi.get_environment()
-    assert isinstance(esxi.get_device_warnings(), list)
+    assert isinstance(esxi.get_hypervisor_hosts(), list)
+    assert isinstance(esxi.get_licenses(), list)
     assert isinstance(esxi.get_lldp_neighbors(), dict)