Add nvs "wifi_ps" to disable wifi power save mode - release

Set disable_ps = n to disable power save mode. This may help with wifi
signal stability, but will likely result in a higher power consumption.

components/wifi-manager/wifi_manager.c

@@ -272,10 +272,18 @@ void wifi_manager_init_wifi(){
     ESP_LOGD(TAG,   "Initializing wifi. Setting WiFi mode to WIFI_MODE_NULL");
     ESP_ERROR_CHECK( esp_wifi_set_mode(WIFI_MODE_NULL) );
     ESP_LOGD(TAG,   "Initializing wifi. Starting wifi");
-	if (gpio36_39_used) {
-		ESP_LOGW(TAG, "GPIO 36 or 39 are in use, need to disable WiFi PowerSave!");
-		esp_wifi_set_ps(WIFI_PS_NONE); 
+	char * disable_ps = config_alloc_get_default(NVS_TYPE_STR, "disable_ps", "n", 0);
+
+    if (gpio36_39_used || (disable_ps && strcasecmp(disable_ps,"y"))) {
+		if(gpio36_39_used){
+			ESP_LOGW(TAG, "GPIO 36 or 39 are in use, need to disable WiFi PowerSave!");
+		}
+		else {
+			ESP_LOGW(TAG, "wifi powersave config is disabled. Disabling WiFi PowerSave!");
 		}
+		esp_wifi_set_ps(WIFI_PS_NONE); 
+	}
+    FREE_AND_NULL(disable_ps);
     ESP_ERROR_CHECK( esp_wifi_start() );
 
     taskYIELD();