v0.8.0

BLU devices that a gateway only relays get a row of their own, and a wizard tells
you which model they are.

Added

• Rows for BLU devices that a gateway only relays (BLE.CloudRelay): readings,
  buttons and sensors from their BTHome messages; read only — no backup, restore
  or logs. The model is estimated from what the device sends ("?") until it is
  identified; a name can be given under Notes.
• Identify BLU devices: a wizard in which a gateway listens while you put a BLU
  device in pairing mode, and shows the model of every device that answers. The
  model is stored in ShellyLanMan's archive; nothing changes on the device or the
  gateway. On the Devices page (Identify) and in the checklist's BLE dialog.
• API: relay in the device list, GET /api/v1/blu/gateways,
  POST /api/v1/blu/identify (events blu.identify, blu.discovered), and an
  optional name when saving the notes of a relayed BLU device.

Changed

• README: screenshots with a relayed BLU device and the Identify wizard.