- Included the `shutdown` command in the Qtech interface template to manage interface states.
- Updated expected output JSON files to set the `shutdown` attribute to true for accurate testing and validation of interface configurations.
- Added a `shutdown` boolean attribute to the `Interfaces` class to manage interface states.
- Updated the `eltex.ttp` template to include the `shutdown` command based on the new attribute.
- Modified expected configuration JSON files for various devices to reflect the new `shutdown` attribute, ensuring accurate testing and validation of interface configurations.
- Replaced the internal `_expand_vlan_range` function in the `Qtech` class with the new `expand_vlan_range` utility from `utils.py` for improved code maintainability.
- Added new configuration files `config_1.conf` and `config_2.conf` for Qtech devices to facilitate testing.
- Introduced expected output JSON files `config_1.expected.json` and `config_2.expected.json` to validate the parsing of Qtech configurations against expected results.