added initial support for hydroponic systems, changed cooldown to use minutes

esp32/include/HomieTypes.h

@@ -13,8 +13,12 @@
 
 #include <Homie.h>
 
+//plant pump is deactivated, but sensor values are still recorded and published
 #define DEACTIVATED_PLANT -1
+//special value to indicate a missing sensor when the plant is not deactivated but no valid sensor value was read
 #define MISSING_SENSOR -2
+//plant uses only cooldown and duration, moisture is measured but ignored, allowedHours is ignored (eg. make a 30min on 30min off cycle)
+#define HYDROPONIC_MODE -3
 
 typedef struct PlantSettings_t
 {
@@ -22,7 +26,7 @@ typedef struct PlantSettings_t
     HomieSetting<long> *pPumpAllowedHourRangeStart;
     HomieSetting<long> *pPumpAllowedHourRangeEnd;
     HomieSetting<bool> *pPumpOnlyWhenLowLight;
-    HomieSetting<long> *pPumpCooldownInHours;
+    HomieSetting<long> *pPumpCooldownInMinutes;
     HomieSetting<long> *pPumpDuration;
 } PlantSettings_t;