Multiple small fixes required to make this install on HP hardware and some spelling corrections in README.md

Admittedly this MR contains a whole bunch of little tweaks. If this MR is annoying and unweildy, let me know and I'll resubmit separately.

• Add a case statement to oci-system-serial to make motherboard serial number detection more flexible (and make installation possible on NUC or other non-"enterprise" hardware. From testing several consumer-grade boards, I found that many of them report an empty string for system-serial-number)
• Do the same thing with common/usr/bin/openstack-cluster-installer-agent
• Comment out the duplicated [server_ext] in etc/openstack-cluster-installer/pki/oci-ca.conf that seems to prevent oci-gen-slave-node-cert from actually generating slave certs
• enable SSL monitoring for Wallaby release of Glance in puppet/manifests/controller.pp
• ENC: remove networks.role='ipmi' from the ceph cluster network query, as it would otherwise always fail to return a network role
• ENC: remove "AND networks.role='vip'" from the vm-net network query, as it would otherwise always fail to return a network.
• Fixes for NIC firmware version detection (NET_FIRMWARE_VERSION) and null in switchport name. Frustratingly, ethtool version 5.9 puts commas in the firmware version output with igb cards:

driver: igb version: 5.10.0-11-amd64 firmware-version: 1.70, 0x80001060, 1.2836.0

this behaviour seems dependent on the network driver, as the same doesn't happen on i40e, e1000e, r8152, r8169, orthe various USB and wifi NICs I have tried it on:

driver: i40e version: 5.10.0-11-amd64 firmware-version: 5.60 0x8000355f 1.1752.0 expansion-rom-version:

• Turn off biosdevname=0 net.ifnames=0 in bin/openstack-cluster-installer-build-live-image as this made it very hard to configure the network in unusual ways
• minor spelling corrections in README.md