Add available_ble_devices() method

[lukipuki]

Summary
The available_ble_devices() is requested by many users to detect BLE devices running Meshtastic.

Also refactored BleHandler:

• added available_peripherals method, factoring out logic out of BleHandler::find_ble_radio.
• added comments
• added BleDevice struct with name (optional) and MAC address

Related Issues
#32

Checklist

• Tests pass locally
• Documentation updated if needed

[andrewdavidmackenzie]

Need to make public the BleDevice struct, in the stream module like BleId?

[lukipuki]

Need to make public the BleDevice struct, in the stream module like BleId?

Made it public, also added Clone and Eq.

[andrewdavidmackenzie]

Could I request Debug too please? 🙏

[lukipuki]

Done

[andrewdavidmackenzie]

BleId implemented from_name(). WOuld be useful here too, I think not available?

[lukipuki]

Doesn't this work?

if let Some(name) = ble_device.name {
    let ble_id = BleId::from_name(&name);
}

We can add more convenience functions, but right now I want to focus on core functionality. I can add more in followup PRs.

[lukipuki]

The implemented From<BDaddr> suggests how it's supposed to be used (ble_device.mac_address.into()), using the name is only more fragile than a MAC address which is unique.