Implement HwmonTemperatureSensor, add serialization

app/src/HwmonTemperatureSensor.cxx

@@ -0,0 +1,33 @@
+#include <boost/json.hpp>
+#include <boost/json/parse.hpp>
+#include <sensors/sensors.h>
+
+#include <HwmonTemperatureSensor.h>
+
+using namespace boost::json;
+
+#define SENSOR_TYPE_STRING "HWMON"
+
+int HwmonTemperatureSensor::getTemperature() {
+  double *value;
+  sensors_get_value(&mChipName, mSubFeature.number, value);
+
+  return static_cast<int>(*value);
+}
+
+void tag_invoke(value_from_tag, value &jv, sensors_bus_id &c) {
+  jv = {{"type", c.type}, {"nr", c.nr}};
+}
+
+void tag_invoke(value_from_tag, value &jv, sensors_chip_name &c) {
+  jv = {{"prefix", c.prefix},
+        {"sensors_bus_id", value_from(c.bus)},
+        {"addr", c.addr},
+        {"path", c.path}};
+}
+
+std::string HwmonTemperatureSensor::toJson() {
+  value jv = {{SENSOR_TYPE_STRING, {"ChipName", value_from(mChipName)}}};
+
+  return serialize(jv);
+}