Adds scripts/generate_weathermap.py: fetches device inventory and
connectivity-matrix from IPFabric, cross-checks IPFabric's abbreviated
interface names against the live gnmic exporter, and emits a Grafana
dashboard-as-code JSON (configs/grafana/weathermap-dashboard.json) with
the weathermap-ng panel wired to explicit legendFormat-resolved queries
for BGP status, interface tx/rx, and VXLAN MAC-per-VNI.
Refs #48
