Allow changing CONFIG_ESP_WIFI_ESPNOW_MAX_ENCRYPT_NUM to 20 for esp-now

[ProfFan]

Call esp_now_add_peer() to add the device to the paired device list before you send data to this device. If security is enabled, the LMK must be set. You can send ESP-NOW data via both the Station and the SoftAP interface. Make sure that the interface is enabled before sending ESP-NOW data.

The maximum number of paired devices is 20, and the paired encryption devices are no more than 17, the default is 7. If you want to change the number of paired encryption devices, set CONFIG_ESP_WIFI_ESPNOW_MAX_ENCRYPT_NUM in the Wi-Fi component configuration menu.

A device with a broadcast MAC address must be added before sending broadcast data. The range of the channel of paired devices is from 0 to 14. If the channel is set to 0, data will be sent on the current channel. Otherwise, the channel must be set as the channel that the local device is on.