Add: concept of preset to zapper-iot connector

[p-gentili]

Description

This PR adds support for the preset key in the provision_data for zapper-iot connector.

Some minor changes:

• renamed url to urls
• overwrite the username/password
• passing reboot_script from config

Resolved issues

Part of ZAP-998

Documentation

N/A

Web service API changes

N/A

Tests

Tested running testflinger-device-connector zapper_iot provision --config config.yaml job.json with

# config.yaml
device_ip: 10.102.162.85
control_host: 10.102.242.85
reboot_script:
  - snmpset -c private -v2c 10.102.196.146 .1.3.6.1.4.1.13742.6.4.1.2.1.2.1.8 i 0
  - sleep 30
  - snmpset -c private -v2c 10.102.196.146 .1.3.6.1.4.1.13742.6.4.1.2.1.2.1.8 i 1
  
# job.json
  {
    "provision_data": {
        "preset": "Tillamook",
        "urls": [
            "https://tel-image-cache.canonical.com/oem-share/tillamook/uc20/uc20-gm/tillamook-core-20-gm-20230905-16.tar.gz"
        ]
    },
    "test_data": {
        "test_username": "admin",
        "test_password": "admin"
    }
}

[kiya956]

I have done some tests on my device, and I think it's good