[SYS][BREAKING] Add gateway states, Offline mode and refactor sleep (#2020)

Gaterway states to improve LED management
Make the sleep function accessible outside BT
BREAKING remove sleep for ESP8266
BREAKING lowpowermode API changed to powermode and new mode definition

Co-authored-by: Florian <1technophile@users.noreply.github.com>

main/ZsensorDS1820.ino

@@ -159,10 +159,8 @@ void MeasureDS1820Temp() {
           String origin = String(OW_TOPIC) + "/" + ds1820_addr[i];
           DS1820data["origin"] = origin;
           handleJsonEnqueue(DS1820data);
-          delay(10);
-#  if defined(DEEP_SLEEP_IN_US) || defined(ESP32_EXT0_WAKE_PIN)
-          ready_to_sleep = true;
-#  endif
+          if (SYSConfig.powerMode > 0)
+            ready_to_sleep = true;
         } else {
           Log.trace(F("DS1820: Temperature for device %s didn't change, don't publish it." CR), (char*)ds1820_addr[i].c_str());
         }