feat: read-only IPMI driver; report a missing Redfish license (0.2.0)

A Supermicro X10DRL-i refuses Redfish without a license (SUM, DCMS or
OOB), even the service root. IPMI answers without one.

- New entry point `ipmi` (napalm_redfish.ipmi.IpmiDriver) on
  ManagementControllerDriver, over pyghmi: facts and inventory from the
  FRU (serial number, system UUID), the BMC's LAN interface, sensors
  (temperatures, fans, power supplies), the power state, the event log
  and the BMC firmware. Read-only: no power control, no BMC reset.
  Tested against recordings of the X10 with serials, the UUID, MACs and
  IPs replaced.
- RedfishDriver.open() no longer fails on a license refusal: get_facts
  returns what is known without Redfish, get_device_warnings reports
  bmc_license_required with the licenses the BMC names, every other
  getter raises. netOrk then shows the reason instead of an offline BMC.
- IpmiDriver is not exported from the package: NAPALM's own
  get_network_driver("redfish") takes the first driver class of
  napalm_redfish.

pyproject.toml

@@ -4,7 +4,7 @@ build-backend = "setuptools.build_meta"
 
 [project]
 name = "napalm-redfish"
-version = "0.1.2"
+version = "0.2.0"
 description = "NAPALM driver for server baseboard management controllers over DMTF Redfish"
 readme = "README.md"
 license = { file = "LICENSE" }
@@ -14,6 +14,7 @@ dependencies = [
     # Not on PyPI: install from git before this package (see README).
     "napalm-device-types>=4.8",
     "redfish>=3.2",
+    "pyghmi>=1.5",
 ]
 classifiers = [
     "License :: OSI Approved :: Apache Software License",
@@ -30,6 +31,7 @@ test = [
 
 [project.entry-points."napalm.drivers"]
 redfish = "napalm_redfish:RedfishDriver"
+ipmi = "napalm_redfish.ipmi:IpmiDriver"
 
 [tool.setuptools.packages.find]
 include = ["napalm_redfish*"]