feat: report the licenses a BMC asks for as facts (0.5.0)

get_licenses (napalm-device-types LicenseMixin, 4.15) on redfish and bmc,
for NetOrk/netork#1111.

- A BMC that refuses Redfish altogether reports each license it names as
  missing, with its message.
- One that answers but withholds parts reports the license with withholds,
  e.g. DCMS withholding drives and the firmware inventory on an X10 with
  only SFT-OOB-LIC.
- ipmi knows no licenses.

get_device_warnings keeps its two codes until netOrk derives them.

tests/test_bmc_driver.py

@@ -156,3 +156,12 @@ def test_over_ipmi_the_protocol_netork_talks_is_known_to_be_on(unlicensed):
 def test_the_bmc_is_not_reset_over_ipmi(unlicensed):
     with pytest.raises(RuntimeError, match="needs Redfish"):
         unlicensed.reboot_host()
+
+
+def test_the_license_facts_are_redfish_s_even_while_ipmi_reads(unlicensed):
+    assert [lic["name"] for lic in unlicensed.get_licenses()] == ["SUM", "DCMS", "OOB"]
+
+
+def test_ipmi_knows_no_licenses():
+    assert not hasattr(ipmi.IpmiDriver, "get_licenses")
+    assert callable(getattr(BmcDriver, "get_licenses", None))