feat: add get_device_info.srv service for device information and parameters (model, serial number, firmware)

[andreacalm]

• Added a new ROS service, /get_device_info, returning model, serial, and firmware for Axis cameras.
  Implemented Axis VAPIX retrieval with fallback logic:
  primary: /axis-cgi/basicdeviceinfo.cgi (JSON, newer firmware),
  fallback: param.cgi groups for firmware/model/serial (older models/firmware compatibility).
• Added startup ROS params publication:
  • ~device/model
  • ~device/serial
  • ~device/firmware
• Added startup logging with detected device info and robust error handling (unknown when data is unavailable).
• Standardized the service name as global /get_device_info to avoid namespace differences across launch configurations.
• Refactored device-info logic into a shared module to remove duplication between nodes.
• Verified with catkin_make and runtime checks (rosservice/rosparam) successfully.

Note: on some cameras/users, serial may remain unknown due to endpoint permission limitations, which is expected behavior.