[LPM] ESP8266 and DS1820 DeepSleep (#1591)

Add support for the ESP8266 deep sleep and required change for DS1820 sensor used in my project.

Allow defining DS1820_RESOLUTION and DS1820_INTERVAL_SEC in ENVIRON without editing config file.

Allow DTimeBetweenReadingmq2 Env. MACRO change without editing source config file.

Added some an example ENVIRONMENTS

Add ESP8266_DEEP_SLEEP_IN_US to nodemcuv2-all-test

main/ZsensorDS1820.ino

@@ -162,6 +162,9 @@ void MeasureDS1820Temp() {
           Log.trace(F("DS1820: Temperature for device %s didn't change, don't publish it." CR), (char*)ds1820_addr[i].c_str());
         }
         persisted_temp[i] = current_temp[i];
+#  ifdef ESP8266_DEEP_SLEEP_IN_US
+        ready_to_sleep = true;
+#  endif
       }
     }
   }