Add H3C device support with configuration and expected output files

- Introduced support for H3C devices by adding a new configuration file `config.conf` containing interface and VLAN settings.
- Created an expected output JSON file `config.expected.json` to validate the parsing of H3C configurations.
- Updated the test model cases to include H3C for comprehensive testing of device parsing functionality.

tests/test_models.py

@@ -12,6 +12,7 @@ MODEL_CASES = [
     ("qtech", "config_2.conf", "config_2.expected.json"),
     ("huawei", "config.conf", "config.expected.json"),
     ("eltex", "config.conf", "config.expected.json"),
+    ("h3c", "config.conf", "config.expected.json"),
     ("quasar", "config_1.conf", "config_1.expected.json"),
     ("quasar", "config_2.conf", "config_2.expected.json"),
 ]