Add controller info endpoint model (Related issue: #75)

[rubempoli]

Related issue: #75

This PR exposes the diagnostic information returned by the Omada Controller /api/info endpoint as OmadaControllerInfo.

The library already uses /api/info internally to retrieve controllerVer and omadacId. This change keeps the existing _get_controller_info() behavior intact and adds a public get_controller_info() method exposing the remaining fields returned by the API.

Fields exposed:

• controllerVer
• apiVer
• configured
• type
• supportApp
• omadacId
• registeredRoot
• omadacCategory
• mspMode
• omadaCloudUrl

This is useful for consumers such as Home Assistant to represent the Omada Controller itself as a diagnostic entity.

The existing hardware controller firmware/update helpers are not changed.

Validated against Omada Software Controller 6.2.10.15.

Local validation:

• git diff --check
• python -m compileall src
• local call to get_controller_info() against Omada Software Controller 6.2.10.15
• local Home Assistant custom integration test exposing:
  • Omada Controller Device Status
  • Omada Controller Version
  • Omada Controller API Version

Home Assistant behavior validated locally:

• connected: /api/info responds with configured=true
• unavailable: Omada Controller service stopped / /api/info unreachable
• disconnected: simulated controller not operational state