Add configurable option to set BLE Power level

[corneliusmunz]

It would be good to enable the user to set the BLE Power level without calling NimBLE-Arduino functions. Maybe the default levels could be changed from -3dB to +9dB

The power levels for scan, advertisment and default could be changed with the static NimBLE-Arduino function
void NimBLEDevice::setPower(esp_power_level_t powerLevel, esp_ble_power_type_t powerType)

With esp_power_level_t

/*
ESP_PWR_LVL_N12 = 0, Corresponding to -12dbm
ESP_PWR_LVL_N9  = 1, Corresponding to  -9dbm
ESP_PWR_LVL_N6  = 2, Corresponding to  -6dbm
ESP_PWR_LVL_N3  = 3, Corresponding to  -3dbm
ESP_PWR_LVL_N0  = 4, Corresponding to   0dbm
ESP_PWR_LVL_P3  = 5, Corresponding to  +3dbm
ESP_PWR_LVL_P6  = 6, Corresponding to  +6dbm
ESP_PWR_LVL_P9  = 7, Corresponding to  +9dbm
*/

and esp_ble_power_type_t

/*
ESP_BLE_PWR_TYPE_ADV        = 9,  For advertising
ESP_BLE_PWR_TYPE_SCAN       = 10, For scan
ESP_BLE_PWR_TYPE_DEFAULT    = 11, For default, if not set other, it will use default value
 */

@fvanroie : I've seen this in your code and thought that this would be a good way to increase the usable distance of the BLE connections to the hubs. Do you have faced any issues about remarkable lower battery lifetimes?

[fvanroie]

Good idea!

I don't have much data I'm afraid, I only included that line because the HubRemote Led was sometimes blinking when bad reception. This annoyed/distracted me, so I upped the power level of the ESP32 😄 .