feat: switch the server's power over IPMI (0.3.0)

IpmiDriver.set_power_state sends an IPMI chassis control: On, GracefulShutdown,
ForceOff and ForceRestart. get_power_state now offers what fits the server's
state: On when it is off, the other three when it is on. IPMI has no graceful
restart and pyghmi offers no power cycle, so neither is offered. The driver
still does not reset the BMC.

For boards that offer nothing but IPMI, such as a Supermicro X10 without a
Redfish license.

pyproject.toml

@@ -4,7 +4,7 @@ build-backend = "setuptools.build_meta"
 
 [project]
 name = "napalm-redfish"
-version = "0.2.1"
+version = "0.3.0"
 description = "NAPALM driver for server baseboard management controllers over DMTF Redfish"
 readme = "README.md"
 license = { file = "LICENSE" }