Refactor Qtech model to utilize centralized VLAN range expansion utility

- 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.

tests/fixtures/qtech/config_2.conf

@@ -0,0 +1,36 @@
+! QTECH LLC Internetwork Operating System Software
+! QSW-8330-40T-DC Series Software, Version 2.2.0C Build 96279, RELEASE SOFTWARE
+! ROM: System Bootstrap, Version 0.4.7,hardware version:A
+! Serial num:6060606060606060, ID num:555555555555
+! System image file is "Switch.bin"
+! QTECH LLC QSW-8330-40T-DC RISC
+! 524288K bytes of memory,16384K bytes of flash
+! Base ethernet MAC Address: 08:c6:b3:08:cf:f7
+! snmp info:
+!   vend_ID:27514   product_ID:404   system_ID:1.3.6.1.4.1.27514
+interface GigaEthernet1/0/9
+ shutdown
+ description FREE
+ switchport pvid 102
+ storm-control broadcast threshold 15
+ storm-control broadcast action shutdown
+ storm-control broadcast auto_resume 60s
+ storm-control multicast threshold 10
+ storm-control multicast action shutdown
+ storm-control multicast auto_resume 60s
+ qos policy IPP3 ingress
+!
+interface VLAN1
+ ip address 192.168.0.1 255.255.0.0
+ ip mtu 1500
+ no ip directed-broadcast
+!
+interface VLAN1002
+ description test-1002
+ ip address 13.36.8.1 255.255.255.0
+ ip mtu 1500
+ no ip directed-broadcast
+!
+vlan 1,7,14-15,44,101-102,115,117-124,130-136,139,167,200-205,772
+,1607
+vlan 888,2016,2085-2088