Issue #369 - Expand bluetooth repository use cases

Changes:
- Adds support for obtaining bonded devices
- Adds support for obtaining BLE scanner
- Consolidates state into a single, immutable data class instance
- Simplified and renamed broadcast receiver
- Renamed view model permissionsUpdated fun to identify the intended use

(cherry picked from commit 9592fd68de)

app/src/main/java/com/geeksville/mesh/model/BluetoothViewModel.kt

@@ -4,6 +4,7 @@ import androidx.lifecycle.ViewModel
 import androidx.lifecycle.asLiveData
 import com.geeksville.mesh.repository.bluetooth.BluetoothRepository
 import dagger.hilt.android.lifecycle.HiltViewModel
+import kotlinx.coroutines.flow.map
 import javax.inject.Inject
 
 /**
@@ -13,7 +14,11 @@ import javax.inject.Inject
 class BluetoothViewModel @Inject constructor(
     private val bluetoothRepository: BluetoothRepository,
 ) : ViewModel() {
-    fun refreshState() = bluetoothRepository.refreshState()
+    /**
+     * Called when permissions have been updated.  This causes an explicit refresh of the
+     * bluetooth state.
+     */
+    fun permissionsUpdated() = bluetoothRepository.refreshState()
 
-    val enabled = bluetoothRepository.enabled.asLiveData()
+    val enabled = bluetoothRepository.state.map { it.enabled }.asLiveData()
 }