feat: configuration loading and netbox api client

config.yaml next to the script (or $NETBOX_INVENTORY_CONFIG) with environment
variable overrides, requests session with token auth, paginated list fetching
and readable error reporting.

.gitignore

@@ -0,0 +1,18 @@
+# Python
+__pycache__/
+*.py[cod]
+.venv/
+
+# Testing
+.pytest_cache/
+.ruff_cache/
+
+# Configuration
+config.yaml
+
+# IDE
+.idea/
+.vscode/
+
+# OS
+.DS_Store