Add DSCM NetConf Driver and associated test scripts (2nd commit)

- Implemented NetConfDriver for managing device configurations via NETCONF protocol.
- Created run_tests_locally-device-netconf-dscm.sh script for local testing of driver functionalities.
- Added Jinja2 templates for generating configuration XML for hub and leaf devices.
- Developed test cases in test_dscm_netconf_hub_leaf.py to validate configuration retrieval and setting for hub and leaf devices.
- Added example XML files for expected configurations and actual results for testing purposes.