Add mediacast-netcatalog (multi-vendor command catalog + version matcher)

[RobarePruyn]

What

Adds mediacast-netcatalog to the Vendor Abstraction Library section.

Why it fits this list

A YAML-backed catalog mapping abstract command types (ARP_TABLE, MAC_TABLE, INTERFACE_CONFIG, etc.) to concrete CLI strings + protocol alternatives (NETCONF / RESTCONF / gNMI / eAPI / SNMP / Dashboard API) per (vendor, firmware version) for seven switch platforms:

• Cisco IOS / IOS-XE
• Cisco NX-OS
• Aruba AOS-CX
• Juniper Junos
• Arista EOS
• HPE / Aruba ProCurve
• Cisco Meraki MS

Catches the real-world version-aware traps that bite multi-vendor automation:

• Cisco IOS-XE 12.x / 15.x / 17.x output drift on the same show command
• NX-OS ip dhcp relay address vs. IOS ip helper-address
• Aruba AOS-CX firmware family-prefix versioning (FL.10.13.1000 etc.)
• Junos transactional config (configure → set → commit not single-line imperative)
• Arista EOS defaults (MSTP, MTU 9214) that differ from the IOS-compatible CLI surface

Distribution

• crates.io (Rust)
• PyPI (Python via PyO3 bindings)
• Dual-licensed MIT / Apache-2.0
• Currently v0.2 (API may evolve toward v1.0; pin a specific minor version)

Existing-entry alphabetical fit

Placed between Infoblox Go Client and pan-python to maintain the section's alphabetical order.