Add network-graph endpoint

mapping_provider/api/network_graph.py

+from fastapi import APIRouter
+
+from mapping_provider.dependencies import config_dep
+from mapping_provider.services.gap import load_routers, load_trunks
+
+router = APIRouter()
+
+
+@router.get("/network-graph")
+def get_network_graph(config: config_dep):
+    routers = load_routers(config)
+    trunks = load_trunks(config)
+    return {"routers": routers, "trunks": trunks}