WIP: Add networking-lab with devstack-nxsw-vxlan

[hjensas]

Introduces a new networking-lab directory for network-focused scenarios that don't require full OpenShift deployments. Includes first scenario: devstack-nxsw-vxlan with spine-and-leaf topology featuring:

• 4 Cisco NX-OS switches (2 spine + 2 leaf) with OSPF underlay
• Devstack node with trunk port for VLAN-tagged traffic
• 2 Ironic baremetal nodes attached to leaf switches
• Individual POAP scripts and configs per switch
• VXLAN/EVPN ready configuration
• SVG topology diagram
• Automated POAP md5sum management script and pre-commit hook

Point-to-point links consolidated in 10.1.1.0/24 to preserve 10.1.2.0/24+ address space for future use.

[softwarefactory-project-zuul]

Build failed (check pipeline). Post recheck (without leading slash)
to rerun all jobs. Make sure the failure cause has been resolved before
you rerun jobs.

https://softwarefactory-project.io/zuul/t/rdoproject.org/buildset/6c7330cc806f448bb9eaf3bc26ffdf86

❌ hotstack-pre-commit FAILURE in 5m 08s

[softwarefactory-project-zuul]

Build failed (check pipeline). Post recheck (without leading slash)
to rerun all jobs. Make sure the failure cause has been resolved before
you rerun jobs.

https://softwarefactory-project.io/zuul/t/rdoproject.org/buildset/34dc036fde0c4bd98c6012345af47fbe

❌ hotstack-pre-commit FAILURE in 5m 24s

[softwarefactory-project-zuul]

Build failed (check pipeline). Post recheck (without leading slash)
to rerun all jobs. Make sure the failure cause has been resolved before
you rerun jobs.

https://softwarefactory-project.io/zuul/t/rdoproject.org/buildset/ee19a1674fb249b5aaea50d1bafbac52

❌ hotstack-pre-commit FAILURE in 5m 35s

[softwarefactory-project-zuul]

Build failed (check pipeline). Post recheck (without leading slash)
to rerun all jobs. Make sure the failure cause has been resolved before
you rerun jobs.

https://softwarefactory-project.io/zuul/t/rdoproject.org/buildset/7fe5d1e12b2348cf92fe6a1d39849501

❌ hotstack-pre-commit FAILURE in 5m 09s